Bulletin 730 October 1969
W. E. Waters and Charles A. Conover
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Introduction ..... 3 Determination of Salts
Varieties .......... ......... 3 in Irrigation Water 40
Commercial Flower Types. 4 Pinching, Pruning, and
Photoperiodic Response Disbudding .... 40
Groups ............ 5 Pinching .... 40
Structures, Location, Land Field and Bench Crops 40
Preparation, Soil Amendments, Potted Crops 41
and Fumigation ... 6 Pruning 41
Structures ... ........ ----6 Disbudding 41
Location ......... ........ 7 Photoperiod .. .... 42
Land Preparation 7 Lighting .. ... 42
Soil Amendments .... 7 Lighting Systems. 42
Field Soils .8 Length of Light Period
Bench Soils .... 8 Required .. 44
Potting Mixtures 8 Months of Light To
Soil Fumigation ..9 Prevent Bud Set 44
Field Soils ... 9 Black Cloth 45
Greenhouse and Potting Black Cloth Systems 45
Soils ......... 11 Months To Black Cloth To
Stock Plant Production 12 Induce Bud Set . 45
Propagation ..... 13 When To Pull Black Cloth 46
Bench Propagation .... 14 Scheduling 46
Field Propagation 15 Response Groups 46
Spacing and Supporting 17 Timing of Bloom 46
Spacing and Supporting 17 Climatic Effects on Timing 47
Outdoor Production .... 17
Greenhouse Production .. 19 Insects and Mites 48
Pot Plants ... 20 Application of Pesticides 48
Irrigation ... 20 Methods of Application 48
Field Production 21 Application Equipment 49
Methods of Irrigation 21 Phytotoxicity or
Water Quantity and Plant Injury ... 49
Frequency ..... 22 Human Toxicity 49
Greenhouse Production 23 Safety Precautions 49
Methods of Irrigation 23 Insect Pests 50
Water Quantity and Control Suggestions 55
Frequency ... 23 Diseases .55
Pot Production 23 Bacterial and Fungal
Methods of Irrigation 23 Diseases 55
Water Quantity and Viral Diseases .... 55
Frequency ....... ... 24 Control Sugestions 55
Lime, Fertilization, Harvesting, Packaging, Storing
Soluble Salts .. 24 and Keeping Quality ....... 59
Lime ----....------- 24 Harvesting -------- 59
Fertilization ......... 25 Packaging .59
Fertilizer Sources 25 Cut-Flowers .59
Fertilizer Ratios. 25 Potted Mums 60
Nitrogen and Potash 25 Storage .60
Phosphorus .... 30 Wet Storage .. ... 60
Calcium and Magnesium 31 Dry Storage at 310F 60
Boron 31 Storing Pot Mums 62
Copper 34 Lighting in Storage 62
Iron -- 35 Shipping ..62
Manganese and Zinc 35 Keeping Quality ... 63
Soluble Salts 37 Preservatives 63
Fertilizer Salts .. ......... 37 Containers ...... 63
Irrigation Water 38 Water Quality 63
Soluble Salt Control 38 Nutrition and Keeping
Determination of Soluble Quality 64
Salts in Crysthemum
Soils ....... ... 39 Acknowledgments ...... .. 64
W. E. Waters and Charles A. Conover
Dr. Waters is Ornamental Horticulturist and Head, Ridge Ornamental
Horticultural Laboratory, Apopka; and Mr. Conover is Assistant
Ornamental Horticulturist, Florida Agricultural Extension Service,
Florida presently leads the United States in production of
spray type chrysanthemum flowers (pompons). Approxi-
mately 650 acres of pompons with an estimated value of $10
million are produced annually. Although chrysanthemum cut
flowers consist mainly of spray types, approximately $1.8 mil-
lion worth of single flower types (standards) are produced.
This industry has developed since 1949 after it was estab-
lished that high quality chrysanthemums could be grown outside
\ under relativelylight intensity and moderate winter climate.
More recent additions to the industry include potted chrysanthe-
mums and commercial propagation of rooted and unrooted cut-
tings. In addition to local sales, presently about 1.5 million pots
of chrysanthemums are shipped out of Florida annually.
The main production areas for chrysanthemums grown out-
side are from Tampa south along the West Coast and from Vero
Beach south along the East Coast. Relatively small greenhouse
plantings of chrysanthemums are grown throughout the State
This bulletin presents most recent scientific information per-
taining to commercial chrysanthemum production in Florida.
The commercial chrysanthemum grown in Florida is Chrys-
anthemum morifolium Ram. This cultigen is a member of the
Compositae family and is believed to have originated in China.
Numerous varieties were grown in Europe prior to 1800 as
garden flowers. Today hundreds of chrysanthemum varieties
which vary greatly in botanical as well as horticultural charac-
teristics are available through commercial propagators. In this
bulletin varieties are grouped by commercial flower types and
Commercial Flower Types
In this classification system chrysanthemums are divided ac-
cording to usage and culture into groups: single, spray, and
potted flowers (Tables 1, 2, 3).
Table 1. Single-flower chrysanthemum varieties commonly grown in Florida.
Name Group Name Group
White colors Yellow colors
Albatross 9 weeks Amber Bright 8 weeks
Dunlope's White Spider 9 weeks Good News 9 weeks
White Bunbu (spider) 9 weeks Yellow Albatross 9 weeks
Giant Betsy Ross 10 weeks Explorer 10 weeks
Indianapolis White 10 weeks Indianapolis Yellow 10 weeks
White Peter John 12 weeks Yellow Knight (spider) 11 weeks
Yellow Peter John 12 weeks
Pink colors Bronze colors
Pink Chief 8 weeks Amber Bright 8 weeks
Bunbu (spider) 9 weeks Detroit News 9 weeks
Indianapolis Pink 10 weeks Dutchess 9 weeks
Pink Champagne 11 weeks Fireball 9 weeks
Pink Peter John 12 weeks Indianapolis Bronze 10 weeks
Woking Scarlet 10 weeks
Bronze Peter John 12 weeks
Red to deep bronze colors
Mrs. Roy 10 weeks
Table 2. Spray-flower chrysanthemum varieties commonly grown in Florida.
Name Group Name Group
White colors Yellow colors
White Chip 9 weeks Yellow Chip 9 weeks
Hurricane 10 weeks Yellow Starburst (novelty) 10 weeks
Iceberg 10 weeks Yellow Beauregard 10 weeks
Shasta 10 weeks Yellow Iceberg 10 weeks
Starburst (novelty) 10 weeks Yellow Shasta 10 weeks
Pink colors Bronze colors
Blue Chip 9 weeks Bronze Chip 9 weeks
Pink Portrait 10 weeks Beauregard 10 weeks
Valiant 10 weeks Tuneful 10 weeks
Delmarvel 11 weeks
Red to deep bronze colors
Red Jetfire 10 weeks
Red Beauregard 10 weeks
Table 3. Pot-flower chrysanthemum varieties commonly grown in Florida.
Name Group Name Group
White colors Yellow colors
White spider 8 weeks Discovery 9 weeks
Neptune 9 weeks Golden Starburst (novelty) 10 weeks
Snow Clad 9 weeks Jackstraw (novelty) 10 weeks
Commander 10 weeks Yellow Princess Anne 10 weeks
Oregon 10 weeks Yellow Delaware 10 weeks
Starburst (novelty) 10 weeks Yellow Scepter 10 weeks
Pink colors Bronze colors
Bravo 8 weeks Bronze Floridan 9 weeks
Bridesmaid (Fugi) 9 weeks Bronze spider 9 weeks
Floridan 9 weeks Bridegroom (Fugi) 10 weeks
Americana 10 weeks Bronze Americana 10 weeks
Princess Anne 10 weeks Bronze Scepter 10 weeks
Mermaid 10 weeks Delaware 10 weeks
Blue Ridge 11 weeks Princess Anne 10 weeks
Red to deep bronze colors
Red Quill 9 weeks
Red Star 10 weeks
Spitfire 10 weeks
Warhawk 10 weeks
Single-flower Group This group includes all types of
chrysanthemums disbudded to produce a single flower per stem
and known in the trade as singles, standards, commercials, and
disbuds. Numerous flower types including the large-flowered
spray types, large-flowered mums (standards), anemones, Fuji,
spiders, and novelties may be grown in the same manner.
Spray-flower Group A major portion of the chrysanthe-
mums grown in Florida are of this group, and include those
types grown with or without the terminal bud removed to allow
more uniform development of flowers in the spray. This group
is referred to in the trade as pompons; however, many other
types including anemones, decorative, daisies, Fuji, spiders,
and novelties may be grown in this manner.
Pot-flower Group Single and spray-flowered chrysanthe-
mums which may be produced on relatively short stems by
manipulating cultural practices are in this group.
Photoperiodic Response Groups
Chrysanthemums bloom under short days and long nights;
therefore, they are termed photoperiodic. Length of time re-
quired to bloom chrysanthemums from initiation of favorable
photoperiods varies from 8 to 12 weeks for commercial varieties
grown in Florida; therefore, plant propagators classify chrys-
anthemums in response groups based on length of time required
to bloom. For example, a variety that blooms in approximately
10 weeks after initiation of short days is listed in the 10 weeks
response group. Since hundreds of varieties are available, Tables
1, 2, and 3 contain only the most predominant varieties grown
in Florida today. They are listed by color, commercial flower
type, and response group.
STRUCTURES, LOCATION, LAND PREPARATION,
SOIL AMENDMENTS, AND FUMIGATION
Chrysanthemums are grown outside in ground beds under
full sun, under "natural color" saran, and in greenhouses. The
saran is supported by a network of heavy galvanized wire and
posts. The house should be constructed to permit easy operation
of tractor drawn equipment, and saran should be mounted to
the wires for easy removal during hurricanes or off seasons
(Figure 1). Heavy nylon cord that is easily cut is suggested for
mounting saran instead of metal S-hooks. Chrysanthemums may
be grown in glass or plastic houses constructed to permit maxi-
Figure 1. Saran mounted with nylon cord.
mum natural light intensity for normal crop response. Ade-
quate temperature control is required for high quality produc-
Water control, quality of irrigation water and temperature
are important factors in determining location of outdoor chrys-
anthemum production areas. Irrigation water sources should
be checked for soluble salts prior to any land development. Ac-
ceptable soluble salt levels are given in the chapter on fertilizers
and salts. Chrysanthemums should be planted on well drained
land where surface flooding can be avoided and provision made
to carry off excess water by tile drains. Winter plantings should
be located in the warmer coastal areas. Information on local
temperature variations may be obtained from the local U. S.
Weather Bureau Office.
Before any leveling is started, fields must be ditched and tile-
drained for rapid removal of rainfall. Beds should be elevated
4 to 6 inches above aisles to prevent surface water from run-
ning through plants and carrying diseases and other plant pests
during periods of heavy rainfall. Beds should be arranged in a
north to south direction for maximum light utilization and
should be about 4 feet wide with 2-foot aisles. Most newly cul-
tivated soils in Florida need dolomitic or calcic limestone; super-
phosphate, copper sulfate, and borax incorporated to a depth of
6 inches prior to planting the first crop. Details on rates are
reported in the chapter on fertilizers.
Amendments are used primarily to improve soil physical con-
dition, aeration, and moisture or nutrient holding capacities.
Amendments may be grouped into two broad groups, inorganic
Inorganic amendments include several calcined clays, perlite,
and vermiculite. These materials have one great advantage in
that they do not decompose in the soil, and once sufficient quan-
tities have been added, they do not need to be replaced annually.
However, initial cost of adding sufficient quantities of these ma-
terials to field soils is very high.
Organic amendments available in Florida include bagasse,
garbage compost, imported peat moss, Florida peat, shavings,
sawdust, and pine bark. All of these amendments decompose in
the soil, and repeated applications are necessary.
Since there is considerable variation from one farm to an-
other in soils and soil mixtures used, the properties of several
soil amendments are listed in Table 4 to help growers select ma-
terials best suited to their needs.
Table 4. Some chemical and physical properties of several soil amendments.
Water holding Cation exchange capacity
Amendments Avg. pH capacity%* m.e./100g**
Calcined clays 5-5-6.5 50-75 15-25
Perlite 7.0-7.5 10-20
Vermiculite 7.0-7.5 75-150 40-50
Bagasse 5.5-6.5 75-150 15-25
Florida peat 4.0-6.0 100-200 20-40
Garbage compost 6.5-7.5 100-150 25-35
Imported peat 3.5-4.5 100-200 25-50
Shavings 5.5-6.5 75-100
Sawdust 5.5-6.5 100-125 10-15
Shredded pine bark 4.0-4.5 100-125 15-20
*Water holding capacity is percentage of water based on dry weight of soil remaining
in the soil after gravitational water has drained downward following a heavy irrigation
**Cation exchange capacity is a measure of the soil's ability to hold fertilizer nutrients
against leaching and is measured in milliequivalents per 100 grams of dry soil. C.E.G.
readings appear low because they were determined on the standard media particle sizes
without first pulverizing them.
Field Soils Newly developed land for chrysanthemums
should receive a 1 to 11 inch layer of an amendment incor-
porated the first year and about a 12 inch layer incorporated
each subsequent year until the desired soil mixture is attained.
Calcined clay is suggested as an inorganic source and imported
peat or shredded pine bark as organic amendments for field use.
Individual pieces of the amendment should be between /3 and
1/2 inch in diameter.
Bench Soils Greenhouse bench grown chrysanthemums
are more intensively grown than those in field production; there-
fore, additional amendments are incorporated to increase water
and nutrient holding capacities. Usually an amendment such
as peat moss is mixed 50-50 by volume with native Florida sands.
During each subsequent year, from 10% to 20% additional
amendment is added to maintain the original amendment level,
or soils are changed. Where drainage or aeration is a problem,
perlite or a calcined clay should be used.
Potting Mixtures Media for pot-grown chrysanthemums
must provide good aeration, be well drained, and yet hold suf-
ficient water and nutrients for plant growth. Preferably, media
components should be light weight to reduce handling and ship-
No one amendment or combination of native soils will meet
all needs; therefore, artificial mixtures must be made by using
various combinations of soil and amendments listed in Table 4.
Recent research has shown that addition of organic soil amend-
ments to native sandy soils at volumes greater than 50% does
not appreciably increase the water or nutrient holding ability.
However, where a reduction in shipping weight is desired, ad-
dition of larger amounts of organic or inorganic materials may
be economical. Use of very light-weight media is not suggested
for field production, because pots are easily blown over.
No one recommendation will be acceptable for media for
each grower, but in general from 25% to 75% of the media
may be composed of one or more organic amendments and the
remainder composed of native sandy soil. Higher levels of or-
ganic amendments or inclusion of perlite or calcined clay may
be necessary in tight sands or for plants grown in plastic pots
since aeration and drainage may be a problem. Some suggested
soil mixes follow:
50% sandy soil + 50% peat moss
40% sandy soil + 40% peat moss + 20%? perlite or calcined
1/3 sandy soil + 1/ peat moss + 1/3 perlite or calcined clay.
Many other media will serve just as well as the above. Addi-
tional information on media mixtures may be obtained from the
University of California Experiment Station Manual 23, 1957.
Field Soils Several soil fumigants are effective against
fungi, nematodes, weeds, and soil insects, if used properly (Table
5). However, effectiveness is influenced by soil moisture, tem-
perature, texture, and physical properties.1,2 The soil must be
cultivated and kept moist for several weeks to provide excellent
bed tilth for proper dispersion of gaseous fumigants. During
cool or extremely wet weather more time is required between
application and planting to allow toxic fumes to dissipate. Fumi-
1H. L. Rhodes, J. A. Winchester, and A. J. Overman. 1966. Nematode Con-
trol Guide for Vegetable Production in Florida. Fla. Agric. Exp. Sta.
"A. J. Overman. 1965. Efficacy of Broad-spectrum Soil Fumigants for Con-
trol of Root-knot Nematodes in Gladiolus. Proc. Fla. State Hort. Soc. 78:
Table 5. List of soil fumigants for chrysanthemums.
Rate Rate per Cover
Material per acre* 600 sq. ft.* required Remarks
Brozone 525 to 71/3 to Yes Cover for 48 hours, then wait 7 to 10 days before
750 lbs. 10.% lbs. planting.
Methyl 870 to 12 to 18 Ibs. Yes Cover for 48 hours, then wait 7 to 10 days before
bromide 1300 lbs. planting.
Steam 180 F for 180 F for Yes Measure soil temperature 6 inches below surface. May
30 min. 30 min. be planted as soon as cool.
Vapam 100 to 1V to No 2 weeks waiting period before planting during warm
(VPM) 125 gal. 1% gal. weather and 3 weeks during cool or wet weather. More
effective when covered for 5 days.
Vorlex 35 to ,% to No 2 weeks waiting period before planting during warm
45 gal. % gal. weather and 3 weeks during cool or wet weather. More
effective when covered for 5 days.
Vorlex-201 35 to ,% to No 2 weeks waiting period before planting during warm
45 gal. % gal. weather and 3 weeks during cool or wet weather. More
effective when covered for 5 days.
*Use lower rates on sandy soils and higher rates on soils or media containing relatively high amounts of organic matter or other amendments.
gants should not be applied if soil temperature is below 50F or
if soil is completely saturated with water. Loamy soils or soils
containing high amounts of organic matter or other amend-
ments require higher rates of fumigants than light sandy soils
Soil fumigants are hazardous and toxic; therefore, the manu-
facturer's label for handling, use, and storage must be followed.
Brozone is injected 4 to 6 inches below the soil surface with
a special applicator and covered with a plastic film immediately.
VPM, Vorlex, and Vorlex-201 are injected 4 to 6 inches deep
with chisel applicators spaced 6 inches apart. VPM may be
drenched with 1 inch of water. The activity of all three fumi-
gants is enhanced if the treated area is covered following treat-
ment. Figure 2 shows a mechanical tarp layer used during fumi-
Greenhouse and Potting Soils Methyl bromide and steam
are the best materials for this purpose. However in enclosed
greenhouses with established plantings, only steam fumigation
is recommended because methyl bromide fumes may be toxic to
nearby plants. Methyl bromide is released from cans or cylinders
into pans under an airtight plastic or tarp cover. Injection
points should not be more than 15 feet apart in the bed for uni-
form coverage. Methyl bromide is highly toxic to man, but
usually contains 2% chloropicrin as a warning agent.
Figure 2. Mechanical tarpaulin applicator for using soil fumigants.
Steam is injected into soil under a cover, and soil tempera-
ture at the coolest point should be maintained at 180 F for 30
minutes. Excessive soil moisture or tightly compacted soil will
reduce effectiveness of steam treatment.
STOCK PLANT PRODUCTION
Maintaining and growing stock plants under Florida con-
ditions may be risky, especially during the summer season, due
to possible disease and insect problems. However, growers may
save considerable money on cutting costs provided they can
maintain clean stock. When growers produce single stem crops
from non-rooted cuttings, the high number of cuttings needed
forces these growers to produce their own cuttings from stock
to reduce the cost of production.
Growers who produce their own cuttings should purchase
newly rooted cuttings from a commercial propagator each time
stock beds are planted and use these to produce needed cuttings.
Stock plant areas should be fumigated and plants replaced at
least once every 4 to 5 months to reduce or prevent disease,
insect, and nematode contamination as well as to prevent crown
budding which may occur on cuttings from old stock.
Rooted cuttings are normally spaced 6 by 8 inches in beds
similar to those planted to flowers. Watering is similar to that
given flowering plants, but fertilization must be adjusted for
plants grown vegetatively. Stock plants should be fertilized
weekly with 30 pounds each of nitrogen and potassium per acre
or biweekly with 50 pounds each, and a 1 to 1 N to K ratio should
be maintained. Insect and disease control is very important on
stock plants, because these plants are the basis of future crops.
Figure 3 shows a field of commercial stock plants in Florida.
Stock plants should be grown under full sunlight for highest
carbohydrate reserve, but use of 20% shade in Florida has not
proved detrimental. Day length must be long at all times to
prevent premature budding of stock and cuttings after plant-
ing. Addition of 4 hours of light per night of 10 foot candles
intensity between 10 p.m. and 2 a.m. should be provided when
natural day length is insufficient. Use of intermittent lighting
or flashlighting is not recommended for stock plant production,
since premature crown budding may result.
No more than 5 or 6 flushes of cuttings should be harvested
before stock plants are replaced. Age of cuttings taken from
stock plants is important, since cuttings taken from hard, or old
stock plants and those taken from tips of old breaks are more
likely to set crown buds, especially with intermittent lighting.
Figure 3. Field of commercial stock plants.
Chrysanthemum propagation is an exacting job, but if care-
ful attention is given to maintaining disease-free stock and
proper environmental conditions, good cutting production can
Cuttings should be obtained from disease-free, properly
grown stock plants by breaking or snapping them just above a
node. Knives or other cutting instruments should not be used,
because they may transmit disease. Cutting length may vary
with variety, cutting use, and time of year, but average length
is between 21/2 to 31/2 inches. Unrooted cuttings can be stored
dry at 310 F for up to 4 weeks if cuttings are available at the
wrong time, or an accumulation of cuttings is needed for specific
planting dates. Cuttings so stored should be placed in polyethy-
lene bags and positioned so air can circulate around bags in the
Although research has shown that cuttings are not photo-
periodically responsive until they have established root systems,
cuttings should be lighted at 10-foot candles for 3 to 4 hours
per night, since it is difficult to determine when cuttings root.
Chrysanthemums root readily, but most propagators use
rooting hormones to increase number of roots and insure more
uniform rooting. Research has shown that use of hormones does
little to decrease time to root, but does increase uniformity of
roots on cuttings. Indole butyric acid (IBA), in a 1% dusting
powder, is the most commonly used rooting hormone. When-
ever hormones are applied to cuttings, they should be dusted
onto the basal end of stems by hand or a small duster. Do not
apply rooting hormones as a dip or dip cuttings into powder,
because these practices may spread disease even though hor-
mone preparations may contain a fungicide.
Chrysanthemum cuttings may be rooted in many different
rooting media including mixtures of peat moss and perlite, ver-
miculite, and other materials that will provide support and
aeration under mist. All benches, rooting media, and tools used
in cutting production should be sterilized before sticking cut-
Mist propagation has produced best rooting under Florida
conditions. Mist timing schedules vary considerably according
to light intensity, humidity, and air movement. Mist schedules
of from 2 to 4 seconds per 5 minutes to 5 to 6 seconds in 10
minutes are being used. Mist schedules will have to be deter-
mined by each propagator for his specific conditions. The best
schedule will provide the least amount of water possible that
will keep a thin film of moisture on foliage.
Cuttings root most rapidly when night temperatures do not
drop below 650F. Addition of bottom heat to maintain a tem-
perature of 70 to 80' in the rooting medium will hasten root-
ing, because application of mist may reduce temperature of the
rooting medium. Chrysanthemum cuttings root fastest under
full sunlight conditions. However, in Florida full sunlight ranges
between 10,000 and 12,000 foot-candles; therefore, use of up
to 20% shade is not detrimental.
When cuttings are stuck they are usually spaced 1 inch
apart in rows 11/ to 2 inches apart and only deep enough to
remain upright (Figure 4). Leaching of nutrients from foliage
occurs with mist application, and some growers apply a nutrient
mist to overcome this problem by using 4 ounces of a 20-20-20
(N, P205, K20) fertilizer per 100 gallons of mist water. Another
method of replenishing some of the nutrient loss is to apply a
light fertilization (11/2 pounds of 20-20-20 per 100 gallons of
water to 400 square feet) about the time first roots form. How-
ever, if stock is properly grown and mist application not ex-
cessive, application of fertilizer in the propagation bed is un-
Figure 4. Bench propagation of chrysanthemum cuttings.
Cuttings should be removed from the propagation bed when
roots are slightly less than 1/. inch long. Rooted cuttings may
be stored for up to 4 weeks at 31'F. Prior to refrigerated stor-
age, cuttings should be placed upright in boxes and covered with
polyethylene to prevent water loss.
Field Propagation (direct field rooting)
Some growers prefer to root cuttings directly in field pro-
duction areas and by-pass bench rooting (Figure 5). These
growers produce a single stem, "non-pinched" crop by placing
from 2 to 4 cuttings per 6 x 8 inch space. Advantages of this
production technique include a reduction of about 2 weeks in
time required for maturity and a reduction in labor, since cut-
tings do not have to be stuck, rooted, pulled, planted in the field,
pinched and pruned. Also a savings is obtained by eliminating
a rooting structure. Field propagation does have disadvantages,
which include rooting delays due to weather, uneven rooting
caused by uneven application of water, uneven crop, and an in-
crease in disease problems.
When mums are direct-rooted, field soil should be amended
with 10 % to 20% peat moss to help maintain even moisture re-
lationships. The soil should be sterilized prior to sticking cut-
tings, and calcium, magnesium and superphosphate should be
Figure 5. Direct field propagation of chrysanthemum cuttings.
added to the bed prior to sticking. Beds should be elevated 6
inches above aisles to allow good drainage while cuttings are
rooting, since large volumes of water are necessary to prevent
Cuttings are stuck directly into growing beds or benches and
then watered to firm soil. Periodic sprinkling with overhead irri-
gation is required to maintain moisture on foliage, A common
sprinkling sequence is 5 minutes on and 10 off, but the schedule
must be adjusted to maintain moisture on foliage at all times.
Field cuttings usually wilt during daylight hours and may ap-
pear to be damaged; however, if moisture is maintained on the
foliage, they will revive during the night. Drainage is very im-
portant in rooting of field cuttings, since poor drainage will pre-
vent proper rooting or cause loss of plants. To control disease
it is often necessary to spray cuttings with Zineb and Captan
about 3 evenings per week, after sprinklers are turned off.
As soon as roots start to appear the sprinkling schedule
should be adjusted to provide proportionately less water until
cuttings become adjusted to normal field watering programs.
Fertilization is started when roots are about inch long, and
a liquid application is made containing about 30 pounds of N
and 30 pounds of K20 per acre. The normal fertilization pro-
gram is started about a week later.
SPACING AND SUPPORTING
Spacing has a considerable effect on quality and quantity of
chrysanthemum crops. Number of square inches allotted per
stem controls size of bloom, stem and flower weight, stem
strength, and spray form. Spacing is influenced also by light
levels, fertilization rates, and crop height and must be calculated
carefully. Too little space will result in production of small,
weak flowers and stems, and too much space results in uneco-
In outside production supporting wire determines to a great
extent the actual spacing. Galvanized welded wire is used with
6 x 8 inch spaces with the 8-inch side parallel to the bed. Most
outdoor production is on 31/2 to 4-foot wide beds of varying
Wire is placed on the beds and plants set within the 6 x 8
inch squares (Figure 6). Supporting stakes are provided at
ends of beds and along edges to prevent the wire from sagging
as it is raised. As the crop grows, supporting wire is raised on
the supports to prevent bending or toppling of the crop.
Two basic types of spacing are used at present. One utilizes
solid planting (plants in each square) and the other an open
center where two spaces are left unplanted in the center of the
bed. There seems to be little difference in production between
methods when the same number of cuttings are used across
beds. Open center beds do have the advantage of reducing dis-
ease problems, because sunlight, air circulation, and spray pene-
tration are improved and beds are easier to plant and harvest.
Table 6 shows effects of spacing on 4-foot beds.
Under outdoor conditions in Florida good flowers can be pro-
duced with spacings that allow 15 to 25 square inches per stem.
Therefore, the following spacing recommendations can be used
on beds of varying width if the suggested area per stem is
provided. A spacing of 15 square inches per stem will provide
maximum production; however, flowers and stems produced with
this spacing are lightweight and only of fair quality. Approxi-
mately 75 % of stems are marketable with this spacing. Market
preference must be considered, since buyers who desire light-
weight bunches with 8 or more stems will determine the market
for flowers from this spacing.
Good quality chrysanthemums are produced with 20 square
inches per stem, which provides a mixture of heavy and light-
weight stems. Most buyers desire bunches with 6 to 8 stems per
Figure 6. Plant spacer 6 x 8 inch galvanized wire.
Table 6. Effects of plant spacing on production of field-grown spray chrys-
No. stems per No. stems in No. square Average no.
6 x 8 inch sq. 8 squares inches per bunches per
across the bed 6 x 8 inches stem square ft. Remarks
4-3-3-3-3-3-3-4 26 15 1.2 Produces fair quality
pinch crop or with light-weight
single stem stems and flowers
3-2-2-2-2-2-2-3 18 21 1.0 Produces good
pinch crop or quality stems
single stem and flowers
4-2-4-0-0-4-2-4 20 19 1.1 Produces good quality
single stem stems and flowers
3-2-3-0-0-3-2-3 16 24 0.9 Produces excellent
single stem quality with heavy
stems and flowers
"*Information obtained from two separate experiments during 1966. Bunches averaged 14
to 16 ounces.
bunch, and this type of bunch is produced when 20 square inches
are allowed per stem. Although maximum production is not ob-
tained with this spacing, increased quality and value per bunch
offset lower production. Approximately 90% of planted stems
are of marketable quality when 20 square inches are allowed
Excellent quality flowers and heavy stems are produced with
spacings of 25 square inches or more per stem, but production
per acre is lower than with closer spacings. Flower bunches
produced are of very high quality, and if premium prices can
be obtained for such flowers, then they are worth producing.
Most bunches produced at a 25-inch spacing or greater will
have only 5 stems per bunch because of heavy stems and large
flower sprays. About 90 % of planted stems are marketable.
When standard chrysanthemums are grown, spacings of 20
to 25 inches per stem are necessary to obtain the quality desired
by most markets.
Greenhouse bench space is expensive, and maximum produc-
tion per square foot is necessary to offset production costs. Two
primary methods of supporting greenhouse chrysanthemums are
welded or plastic wire mesh with 6 x 8 inch spacings or wire
with cross strings. The second method utilizes considerable hand
labor; therefore, it is not recommended.
To obtain maximum utilization of greenhouse space, solid
plantings are made that allow 15 to 20 square inches per stem.
Probably the most common spacing used in greenhouses is grow-
ing three stems on outside rows and two stems on inside rows.
This spacing allows an average of 20 square inches per stem,
and with good environmental control will produce high quality
mums or pompons.
Most pot plants produced in Florida do not require supports
if proper techniques are used. If the plants do grow too high,
they can be supported with a bamboo stake and string.
Most Florida pot mums are produced for out-of-state ,sales
and grown in 6-inch clay pots under natural saran in the field.
Five or 6 cuttings should be placed around the pot edge and
angled outward from the center. This planting method gives
pots a fuller appearance at maturity. Spacing of pots in the
bench or field is important, since pots too closely spaced will
reduce quality. Proper spacing reduces possibility of tall, one-
sided plants with poor quality foliage. Pots should be spaced
so foliage from adjacent plants never touches even at maturity:
Normally, spacing is dependent on rate of fertilization, variety,
and time of year and averages between 170 and 250 square
inches per pot. If plants grow too tall, greater pot spacing will
be necessary to prevent loss of lower leaves.
Although most water removed from the soil by a plant is
lost to the atmosphere through transpiration, the small portion
utilized in photosynthesis is vital in production of carbohydrates
necessary for growth. Therefore, application of the proper
amount of water to chrysanthemums is important in growing
quality flowers. Water stress in a plant even if it occurs for
a short time checks growth. A grower who desires quality
crops as fast as possible should irrigate prior to noticeable wilt-
ing. Some slight wilting may occur on hot, sunny days, even
though soil moisture may be satisfactory, because of a plant's
inability to absorb water sufficiently fast to keep up with trans-
Quality of irrigation water is very important in chrysan-
themum production because of undesirable effects of certain
chemicals found in some waters. When a new well or growing
operation is being planned, water sources should be checked
first for total dissolved constituents. Soluble salt levels should
Table 7. Classes of irrigation water and permissable limits of constituents.*
Electrical Total dis-
conductance solved solids Sodium
E.C. x 103 (salts) per cent of Boron**
Class of water at 250C ppm total solids ppm
1. Excellent less than 25 175 20 .33
2. Good 25-75 175-525 20-40 .33- .67
3. Permissible 75-200 525-1400 40-60 .67-1.00
4. Doubtful 200-300 1400-2100 60-80 1.00-1.25
5. Unsuitable more than 300 2100 80 l 1.
"L. V. Wilcox. 1948. The Quality of Water for Irrigation Use. USDA Tech. Bull. 062:
"'Adjusted for chrysanthemums in Florida.
be below 700 ppm for the water source to be considered good and
generally should not be higher than 1500 ppm. (Additional in-
formation can be found in the section on soluble salts.) Specific
chemicals found in some water that may cause plant injury
include chlorine, fluorine, and boron. Drainage ponds or pools
should not be used for irrigation because they may contain large
numbers of disease organisms. Within broad limits, Table 7 gives
classes of irrigation water as related to chrysanthemum produc-
Most chrysanthemums produced in the field are watered
with overhead sprinklers, but other methods include sub-
irrigation, hand-watering, and crawler or traveling sprinklers.
When field-grown mums are watered, sufficient water must be
applied to compensate for runoff, evaporation, and coverage of
adjacent non-crop areas. When water is applied to foliage, the
application should be made early in the day so it will not remain
on foliage too long. This is especially true when black cloth is
being used. Increased disease problems due to heat and humidity
buildup occur when foliage is wet under cloth.
Methods of Irrigation Overhead irrigation is the most
commonly used method of watering chrysanthemums in Flor-
ida. Lines containing oscillating sprinkler heads are mounted
on the posts holding up the structure about 4 to 6 feet from the
soil. Each sprinkler should be mounted so an overlap of 50%
exists in the sprinkler water pattern. This aids in prevention
of dry spots and helps overcome the effects of wind. A properly
planned and constructed sprinkler system is also valuable for
application of soluble fertilizers and frost protection.
Sub or seep irrigation is an excellent method of watering
without wetting foliage. This system is based on water move-
ment by capillary action upward from an artificially established
water table. Normally main tiles are placed 18 inches beneath
the soil surface with lateral lines spaced 18 to 24 feet apart.
Water from an outside source (well or irrigation canal) is then
allowed to fill main and lateral lines and maintained at about
12 inches below the surface. Although the system can pro-
vide the water needed by the crop, it is not recommended as
the only source of water. During seasons when little rainfall
occurs, evaporation of water from the surface will cause a con-
centration or accumulation of soluble salts from irrigation water
and fertilizers, which frequently causes root injury. Therefore,
some method of applying irrigation water overhead to remove
this salt concentration from root zones is necessary. Usually
hand-watering is not adequate for this purpose, and overhead
irrigation is suggested. Subirrigation has the advantage of not
wetting foliage, affords excellent drainage during heavy rains,
and permits watering after flowers show color without wetting
Hand watering of mums is expensive, and therefore should
be used very rarely except during flowering and when diseases
are troublesome. Application of water to open flowers shatters
blooms and encourages disease development.
Traveling sprinklers self-propelled by a water motor can be
used to reduce labor costs of hand-watering without wetting
Water Quantity and Frequency This aspect of irrigation
is usually controlled manually rather than with automatic equip-
ment. Growers have not attempted to automate irrigation, be-
cause overhead irrigation is used most widely and application
is made simultaneously to crops of different ages.
On sandy soils watering is a daily operation except during
periods of cloudy or rainy weather. At least 1 inch of water
should be applied at each watering, and at least once during
each 2-week period 3 to 4 inches of water should be applied to
leach accumulated soluble salts from root zones. In areas where
good water is available (water with less than 700 ppm soluble
salts) leaching heavily once a month will be adequate. In many
instances leaching will be accomplished by rainfall. Because
of predominately sandy soils in mum production areas over-
watering is difficult to do, provided land is tile drained.
Two methods of producing cut chrysanthemums in green-
houses are raised benches and ground beds, and watering meth-
ods vary accordingly.
Methods of Irrigation Where sprinkler irrigation is used
inside greenhouses, the practices listed for outdoor production
should be followed. Other irrigation systems made by a number
of manufacturers include "Gates" and "Skinner", which apply
water to the soil surface by means of hoses or pipes laid on the
bench. These systems can be used on raised or ground benches
and automated or controlled manually. Hand-watering is still a
common practice for small production areas of mums on raised
Water Quantity and Frequency Thorough watering to al-
low some leaching each time the bench is watered is necessary
to prevent accumulation of soluble salts. Normally application
of 1 inch of water to the bench will provide necessary leaching,
but the bench should be checked to make sure drainage occurs.
High evaporation and transpiration rates under greenhouse
conditions create the need for watering at least once a day.
Most of the million-plus pot chrysanthemums produced an-
nually in Florida are grown outdoors under field conditions.
Only about 10% are greenhouse grown.
Methods of Irrigation When pot mums are grown out-
doors under saran, they are most frequently watered with over-
hNead sprinkler irrigation systems until they show color, and
then by hand. Hand-watering is necessary after flowers start
to open, because the force of sprinkler water may injure petals,
cause bending or breaking of stems, and encourage disease de-
velopment. Much of the water applied through sprinklers never
enters the pots; therefore, a seemingly excessive amount of
water must be applied to provide sufficient moisture.
Growers are beginning to use semi-automatic pot watering
systems such as "Chapin," "E-Flowmatic", and "Stuppy" in out-
door and greenhouse production. These systems provide water
to individual pots through small plastic lines attached to a main
line. By use of timers and hydraulic controls the system may
be made completely automatic; however, many growers still
water pot chrysanthemums by hand, although it is an expensive
Water Quantity and Frequency In outdoor production at
least 1 inch of water is applied daily when plants are small,
and 1 to 112 inches when plants are larger and deflect droplets.
Sufficient water should be applied once a week to leach excess
fertilizer from pots. When hand-watering is done, 1 to 1'. inches
of water is usually sufficient, since water deflection is reduced.
In greenhouse production % pint of water is sufficient per 6-
inch pot per application.
In outdoor production one watering per day is sufficient
except during periods of windy weather with high temperature
and low humidity when two will be required. Requirements of
greenhouse pot chrysanthemums vary considerably with tem-
perature and light levels, but normally they will require water-
ing once a day when small and twice a day when larger (see soil
moisture in amendment section).
In both types of production, water requirements will depend
to some extent on type of pot used. Plants grown in porous pots
such as clay will require more water than those grown in non-
porous ones such as plastic. Under Florida conditions plants
grown in nonporous pots will require about one-third less water
on the average than those grown in clay pots.
LIME, FERTILIZATION, SOLUBLE SALTS
A desirable pH for chrysanthemums is between 5.8 and 6.8.
In addition to controlling soil pH, lime supplies calcium and
frequently magnesium to plants, reduces solubility of potentially
toxic elements such as aluminum and copper, and reduces mo-
bility of phosphorus and most micronutrients that may be
leached from extremely acid soils.
Slowly soluble lime sources such as dolomitic or high calcic
limestone should be applied at least 3 months prior to planting.
If a soil is low in magnesium, dolomite should be used instead
of high calcic limestone since it is composed of approximately
22% magnesium oxide and 30% calcium oxide. Where a rapid
increase in soil pH is desired, hydrated lime may be used; how-
ever, it should not be used at rates greater than 50 % of the total
limestone needed. In soils with a desirable pH, but low calcium
level, gypsum can be used to raise calcium level without affecting
pH. A guide line for rates to use is given in Table 8; however,
a soil test is recommended in advance of planting to determine
specific lime needs. These tests are available through the County
Agricultural Agent's Office.
Chrysanthemums are produced in Florida under widely di-
vergent fertilizer regimes, but proper fertilization programs
will improve flower keeping quality or vase-life, reduce disease
problems, and produce high yields.
Fertilizer Sources Several kinds of fertilizers such as
soluble inorganic, organic, and slowly soluble fertilizers are
available. Soluble inorganic sources of fertilizer are recom-
mended; several are listed in Table 9. Special effort should be
made to select sources which will supply desired elements yet
have a comparatively low total salt index (Table 9). This is
especially important for growers with high levels of soluble salts
in their irrigation water.
Availability of nutrients in organic and slowly soluble fer-
tilizer sources depends upon environmental factors such as soil
temperature, moisture and microbial populations. Therefore,
these materials should be used only on a limited scale until
growers become familiar with peculiarities of each material.
Fertilizer Ratios Approximately a 1:1 nitrogen to potash
ratio for the first 2/3 of the crop cycle is recommended for chrys-
anthemums, and in the latter part of the cycle a ratio of 1 :1 is
recommended. Field and greenhouse experiments have shown
that higher nitrogen levels during the first part of the crop
cycle and less during the latter part greatly improve flower
keeping quality without sacrificing marketable yield.
Potted chrysanthemums should receive about 1/2 pint ferti-
lizer solution per 6-inch pot weekly. The fertilizer solution
should contain about 1 pound each of nitrogen and potash per
100 gallons of solution (Table 8). This amount of nutrients can
be supplied by 2.2 pounds of potassium nitrate (13-0-44) and
2.0 pounds of ammonium nitrate (33.5% nitrogen) in 100 gal-
lons of water.
Nitrogen and Potash Chrysanthemums take up relatively
large quantities of both nitrogen and potassium during the vege-
tative growth state. Field-grown chrysanthemums should re-
ceive about 350 to 400 pounds each of nitrogen and potash per
crop (Table 8). During the first two-thirds of the crop cycle
approximately 30 pounds each of nitrogen and potash per acre
per week are suggested. During the last third of the crop cycle
nitrogen rate should be reduced by at least 50%. Field and green-
house research has demonstrated that if proper nutrition is
maintained for the first 12 weeks, no benefit is derived from
Table 8. Fertilizer and lime recommendations for cut and potted chrysanthemums.
Cut flowers Potted mums
Materials (43,560 sq. ft.) sq. ft. Remarks Rates Remarks
Nitrogen(N) 30 1.1 oz. Apply weekly for first 2/3 of 1 lb/100 gal. 2.2 lbs. potassium nitrate plus
per wk* per wk crop cycle, then reduce amount Apply 7/16 pint 2.0 lbs. ammonium nitrate con-
by at least 50%. Dry fertilizer per 6" pot.* tains 1 lb. N. This is equal to 4
may be applied every 2 weeks, grams (1 level teaspoon) of dry
but N rates should be doubled, mixed fertilizer per 6" pot.
Potash (K,O) 30 1.1 oz. Apply weekly. May be omitted 1 lb/100 gal. 2.2 lbs. potassium nitrate con-
per wk* perwk last 3 weeks of crop cycle if N Apply 7/16 pint tains 1 lb. KO0.
is omitted. Dry fertilizer may per 6" pot.*
be applied every 2 weeks but
K2O rates should be doubled.
Soluble 10 1/3 oz. Apply every 4 weeks if super- V/ lb/100 gal. If superphosphate is incorpor-
Phosphorus per wk per wk phosphate incorporated pre- Apply 7/16 pint ated, then apply soluble P0Os
(P2sO) plant. Otherwise apply weekly. per 6" pot.* every 4 weeks on acid media
mixtures. If superphosphate not
incorporated, apply each time
with N and K20.
SSingle 1300 3 lb. Apply annually, if needed. Will 11 2/2 Incorporated in field soils or
superphosphate as as leach from highly acid sands. lbs./cu. yd. and in potting mix.
(20% P205) needed needed Soils tests helpful in determin-
Dolomite 1000-2000 21/2 Apply as needed to supply cal- 21/2 5 Incorporated in field soils and
limestone as needed 5 lbs. cium and magnesium and to lbs./cu. yd. in potting mix.
as needed slowly raise soil pH. Soil test
helpful in determining calcium
and magnesium needs.
Calcic 1000-2000 21/ Apply as needed to supply cal- 2 4 Incorporated in field soils or in
limestone as needed 5 lbs. cium and raise soil pH. lbs./cu. yd. potting mix.
Hydrated 500-1000 11/ Apply as needed for rapid pH 1 1% Incorporated in field soils or in
Lime as needed 21/ bs. change and calcium supply. May lbs./cu. yd. potting mix.
as needed be broadcast over established
plants if washed off.
Gypsum 1000-2000 21/ 5 lbs. Apply as needed to supply cal- 1 2% Incorporated in field soils or in
as needed as needed cium where pH is already satis- lbs./cu. yd. potting mix.
*For greenhouse production where the crop receives less leaching, the N and K,O rates should be reduced from 30% to 50% for both bench and pot crops.
Table 9. Chemical content and salt index of several fertilizer carriers.*
Chemical tested** index
Ammonium nitrate 35.0 105
Monoammonium phosphate 12.2 30
Diammonium phosphate 21.2 34
Ammonium sulfate 21.2 69
Calcium nitrate 11.9 53
Potassium nitrate 13.8 74
Sodium nitrate 16.5 100
Urea 46.6 75
Potassium chloride 50.0 109
Potassium chloride 60.0 116
Potassium nitrate 46.6 74
Monopotassium phosphate 34.6 8
Potassium sulfate 54.0 46
Sulfate of potash-magnesia 21.9 43
Monoammonium phosphate 61.7 30
Diammonium phosphate 53.8 34
Monopotassium phosphate 52.2 8
Monosodium phosphate 51.4 36
Superphosphate (single) 20.0 8
Superphosphate (triple) 45.0 10
Calcium carbonate 56.0 5
Dolomite 20.0 1
Magnesium sulfate 16.0 44
Gypsum 32.6 8
"*L. F. Rader, Jr., L. M. White, and C. W. Whittaker. 1943. The salt index a measure of
the effect of fertilizers on the concentration of the soil solution. Soils Science: 201-218.
"*By "fertilizer analysis" is meant the per cent N in nitrogen carriers, per cent P,0O in
phosphorus carriers, per cent K20 in potassium carriers, per cent MgO in magnesium
carriers including dolomite, and per cent CaO in calcium carbonate and gypsum.
tSalt index compared against equal weight of sodium nitrate which was assigned a value
later applications of nitrogen or potash. If a liquid fertiliza-
tion program is followed, weekly applications of potassium nitrate
and ammonium nitrate are suggested, since these sources contain
no extra carrier salts, such as chlorides or sulfates, to contribute
to salinity problems. If a dry fertilizer program is followed, 8-0-8
or an 8-0-12 fertilizer is recommended and should be applied ap-
proximately every 2 weeks for the first 12 weeks. Regardless of
fertilization method, at least 50 7 of the total nitrogen should
be in the nitrate form. This is especially important on highly
fumigated soils where the population of nitrifying bacteria has
been reduced; otherwise, ammonium toxicity may develop.
Figure 7. Phosphorus deficiency-reddish to brown bottom leaves.
Figure 8. Calcium deficiency-blunt, small, curled, thickened leaves at the
Figure 9. Magnesium deficiency-interveinal chlorosis and curling of leaves
from base upward.
Table 10. Chemical composition of newly matured chrysanthemum leaves
based on dry weight.
Element (less than) Desirable range (more than)
% % %
Nitrogen 2.5 3.5-5.5 5.5
Phosphorus 0.2 0.3-0.5 0.5
Potassium 2.5 3.5-6.0 6.0
Calcium .25 .5-2.0 2.0
Magnesium .1 .2-1.0 1.0
ppm ppm ppm
Boron 25 35-150 200
Copper 8 10-30 40
Iron 75 100-250 250
Manganese 50 50-250 250
Zinc 10 25-150 150
In greenhouse production where the crop receives less leach-
ing, the nitrogen and potash rates listed for both field and pot
crops should be reduced from 30 % to 50 %. Nitrogen and potas-
sium deficiencies of chrysanthemums are seldom seen in Florida,
because growers usually supply these elements in luxurious
Nitrogen deficiency symptoms include reduction in plant
vigor and small, light colored leaves. In severe cases the lower
leaves are chlorotic (yellowish color) and may have reddish
veins and margins, and in final stages older leaves become
necrotic (dead) beginning at the margins. Yield and flower size
will be reduced as well as flowering date delayed.
Potassium deficiency is first apparent on lower leaves and
then proceeds up the plant. Symptoms include a lack of plant
vigor, small leaves, and weak stems. In extreme cases leaves
develop interveinal and marginal chlorosis followed by necrosis.
Flowering may be slightly delayed and flower size reduced.
Phosphorus In general, phosphorus should be supplied to
soils low in phosphorus and to newly developed land by incor-
porating from 1,000 to 2,000 pounds per acre of 20% super-
After a field has been limed for a few seasons, phosphorus
is readily fixed in the soil as calcium phosphates and is leached
very little. Old agricultural soils frequently have accumulated
large quantities of phosphorus, and additional applications may
be detrimental to the crop. A soil test prior to planting is help-
ful in determining phosphate needs. Superphosphate supplies
calcium and sulfur to plants in addition to phosphorus.
Phosphorus is easily leached from certain virgin acid "flat-
woods" sandy soils of Florida and from potting mixtures made
from these acid sands or acid organic amendments. Many amend-
ments added to acid sands have relatively little phosphate fixing
power, and thus supplemental phosphorus fertilization is recom-
mended after 4 and 8 weeks of growth for any type of chrys-
anthemums grown on acid, sandy media, even though super-
phosphate and dolomite were incorporated (See Table 8).
Phosphorus deficiency symptoms first occur in lower leaves
and proceed terminally. Affected leaves turn reddish to yellow
to brown beginning at the apex. (Figure 7). In general leaf
size of newly developed leaves is reduced, plants have a dull-
grayish hue, and the lower stem portions may develop a deep
purple color. In severe cases flower size is reduced and flowering
may be delayed up to two weeks.
Calcium and Magnesium These elements should be fur-
nished from dolomitic limestone for soils that are low in both
elements. When only calcium is needed, it is easily furnished
by incorporating such liming materials as high calcic limestone,
hydrated lime, and gypsum (see liming section), or by furnish-
ing soluble calcium in the regular fertilizer program. When
only magnesium is needed, it can be furnished from a com-
bination of dolomitic limestone and soluble magnesium sources.
Average application rates are given in Table 8, but a soil test
to determine calcium and magnesium needs is recommended in
advance of soil preparation. In many areas of Florida irrigation
waters contain relatively large quantities of calcium and/or
magnesium, and a water analysis is recommended to help de-
termine proper liming programs.
Calcium deficiency symptoms first appear in the upper vege-
tative growth as blunt, small, curled, thick leaves arranged in
a rosette pattern (Figure 8). In severe cases terminal growing
points and upper leaves die, roots become stubby and turn
brown, and flower peduncles turn brown and break over about
the time flowers show color.
Magnesium deficiency usually appears first as interveinal
chlorosis and curling under of older leaves (Figure 9). Veins
remain green, and eventually reddish colored spots may develop
interveinally and along leaf margins. In severe cases the symp-
toms also occur on upper leaves and flower size may be reduced.
Boron For newly cultivated soils in areas low in boron,
10 pounds per acre (1/3 ounce per 100 square feet) of borax
may be incorporated preplant, or boron may be applied in the
Figure 10. Boron toxicity (right)-marginal and then general leaf necrosis.
Normal leaf on left.
Figure 11. Boron deficiency (right)-thick, brittle, curved leaves with inter-
veinal chlorosis, epidermal cracks, and corky veins. Normal leaf on left.
Figure 12. Copper deficiency- irregular yellow to complete white spots near
leaf margins. Symptoms usually occur first near growing point.
Figure 13. Copper deficiency of potted chrysanthemums in Florida
fertilizer. Chrysanthemum fertilizers should not contain more
than 0.05% B203. If a boron deficiency develops, plants may
be sprayed two or three times with 1.5 pounds of borax or 1.0
pound of Solubor per 100 gallons of water at weekly intervals.
Total amount of boron applied per year should not exceed the
equivalent of 10 pounds of borax per acre, or boron toxicity may
Boron toxicity symptoms include first marginal and then
general necrosis of old leaves, and eventually the entire plant
is affected (Figure 10). In many areas of Florida the irriga-
tion water contains sufficient quantities of boron for chrysan-
themums. If irrigation water contains over 1 ppm boron, it
should not be used for chrysanthemums.
Boron deficiency of chrysanthemums in Florida is seldom
seen, but deficiency symptoms include thick, brittle, downward
curved leaves with epidermal cracks, interveinal chlorosis, and
reddish corky veins and petioles (Figure 11). In extreme cases
growing points may die, and multiple shoots develop which are
in turn affected. Flowers are small, with rough, slightly brown
petal surfaces. Roots are stubby and brown in color and usually
are affected before the leaves.
Copper Deficiencies may occur on new sandy land or in
potting mixtures containing large amounts of Florida peat or
other soil amendments. New soils should have 20 to 30 pounds
per acre (3 to 1.0 ounce per 100 square feet) copper sulfate
incorporated prior to first planting. If a deficiency occurs, copper
may be applied in the fertilizer and plants sprayed three or four
times with 4 pounds per 100 gallons of tribasic copper sulfate.
Dry fertilizer should not contain more than 0.15% CuO and
liquid fertilizer should not contain more than 0.1%.
Copper is easily accumulated in the soil, and excessive use
for several seasons should be avoided. For soils high in copper
the pH should be maintained near 6.5 to make the copper less
Copper deficiency symptoms first appear on uppermost, fully
developed leaves. Leaves are dull green, wilt easily, and have
irregular yellowish to completely white spots near leaf margins,
including small veins (Figures 12 and 13). In severe cases new
terminal growth becomes distorted and chlorotic, and veins on
terminal mature leaves may become completely chlorotic, pro-
ducing an inverse "netting" effect. Flower size is reduced,
flowering is delayed, and in severe cases uneven floral matura-
Iron Deficiencies of iron are very common in chrysanthe-
mums and usually result from a combination of factors includ-
ing high soil pH, accumulation of copper and phosphate in the
soil, root injury from nematodes, excessive water, or over-
fertilization. Control measures include liming old agricultural
land high in copper to pH 6.5, correcting factors damaging root
systems, and applying iron to the plant and soil. On high pH
soils dry fertilizers should contain 20 pounds per ton of chelated
iron concentrate, and liquid fertilizers should contain not more
than 0.2% Fe,O3 equivalent. If iron deficiency occurs, plants
may be sprayed several times with 1 pound of iron oxalate (Nu-
Iron) or 1,; pound of chelated iron concentrate per 100 gallons
of solution. Do not spray flowers showing color.
Iron deficiency symptoms appear first as a yellowing between
veins of younger leaves. In extreme cases the entire terminal
portion of the plant may become chlorotic (Figure 14).
Manganese and Zinc Deficiencies occur less frequently
than iron, partially because large quantities of manganese and
Szinc are added to the soil from fungicidal sprays. If needed,
manganese may be supplied at rates of 0.1% to 0.2% in dry
fertilizer or 0.05% to 0.1% in liquid fertilizer. Deficient plants
may be sprayed with either ', to 1 pound of manganese sulfate
or 1/ pound of manganese chelate per 100 gallons of water.
Do not spray flowers showing color.
Manganese deficiency symptoms include a general pale green
appearance with mild interveinal chlorosis of young leaves, but
veins are not as distinctly outlined as in iron deficiency (Figure
15). Eventually the chlorotic spots may turn whitish to grayish
Zinc may be supplied in the fertilizer or as a foliar spray.
Fertilizer should not contain more than 0.1 % ZnO, and not more
than 14 pound zinc sulfate or pound chelate zinc concentrate
per 100 gallons of water should be applied as a foliar spray.
Zinc deficiency has not been produced in Florida. Lunt, et al.3
in California reported that symptoms were first apparent as the
plant approached the blooming stage, appearing first as small
chlorotic spots which occurred at any position on middle or
upper leaves (Figure 16). The chlorotic spots gradually devel-
oped necrotic spots in the center, and as flowering occurred
symptoms appeared on progressively younger leaves.
30. R. Lunt, A. M. Kofronek, and J. J. Oertli. 1964. Some critical nutrient levels in
Chrysanthemum morifolium, cultivar Good News. Plant Analysis and Fertilizer Problems
Figure 14. Iron deficiency chlorosis of terminal growing areas.
Figure 15. Manganese deficiency-pale green to chlorotic interveinal areas.
Figure 16. Zinc deficiency right) small necrotic spots at any position
on the leaf. Normal leaf on left.
Salts accumulate in the soil primarily from applied fertilizer
and salty irrigation water, and small amounts are contributed by
decaying organic matter. Soil soluble salts are composed pre-
dominantly of ammonium, calcium, magnesium, potassium, so-
dium, bicarbonate, chloride, nitrate, and -.i1f.i.- ions. When
soluble salt level becomes too high, plant roots are damaged
(burned), which reduces their ability to absorb water and nu-
trients. Other symptoms include stunting, excessive wilting,
-n.i:-i,!:il leaf burn, yellowing of new growth, and small flowers.
In mild cases reduction in growth may occur without other vis-
Fcrtilizer Salts Fertilizer is one primary source of soluble
salts in the soil solution. The salt concentration osmoticc pres-
sure) of the soil solution increases as f.-itiil ir...n rates in-
crease. When salt concentration of the soil solution exceeds con-
centration inside plant roots, water moves out of the roots into
the soil, causing partial or complete dehydration and death.
The fertilization program should .-. Ip.1- adequate nutrition
without addition of excessive soluble salts which decrease flower
vase-life and increase plant susceptibility to Botrytis blight.
Various sources of fertilizer nutrients supply different quan-
tities of salt. The relative salt index of equal amounts of several
materials, based on sodium nitrate as 100, is given in Table 9.
For example, twice as much nitrogen can be added from am-
monium nitrate as from equal quantities of sodium nitrate with
only a very slight increase in salt index.
Irrigation Water Deep well water is another important
source of salts. Concentration of soluble salts in Florida well
waters ranges from very few to several thousand ppm. Generally
wells can be classified as low, medium, and high according to
Wells containing less than 700 ppm total soluble salts are
considered in the low class and usually do not cause trouble.
Wells containing from 700 to 1500 ppm salt are in the medium
salt range and may cause trouble, especially during dry seasons
or where frequent but light overhead irrigation is practiced.
Wells containing over 2,000 ppm salt should be avoided as far
as possible for chrysanthemum production.
Soluble Salt Control Irrigation techniques, soil moisture
levels, and media mixtures are the key factors in preventing
soluble salt build up from fertilizer and irrigation water. Fre-
quent, light irrigations in which no water passes through the
root zone of field, bench, or pot plants favor soluble salt ac-
cumulation from fertilizer and well water. As water is used by
the plant or evaporated, salts are left in the soil. This problem
is increased by prolonged dry periods, especially if sub-irriga-
tion is practiced. All chrysanthemum crops should be watered
heavily enough at least every two weeks so that the water moves
excessive salts through the root zone. During wet weather this
is accomplished naturally by rainfall. Laboratory research has
shown that 11/. inches of water passing through a 6-inch root
zone will remove most soluble salts from sandy soil mixtures.
Usually 3 to 4 inches of water are necessary to move 1' inches
of water through the 6 inches of soil containing root systems.
Where sub-surface irrigation is practiced, salts move up-
ward in the water and form a "crust-like" deposit on the soil
surface. Sub-irrigation gates should be opened every 2 weeks and
fields leached by overhead irrigation or rainfall to prevent salt
accumulation. This is especially important where medium to
high salty wells are the main water source.
Where salinity is a problem, crops should not be grown on
the "dry side," as medium to high soil moisture tends to reduce
salt levels. For example, a soil containing 500 ppm salt at 50%
soil moisture will contain approximately 1,000 ppm salt at 25%
Water-holding capacity and cation exchange capacity (ferti-
lizer retention ability) of soil media affect soluble salt level. In
general, as these factors increase, there will be less likelihood
of toxicity to crops, but soluble salt toxicity in heavy or highly
organic soil mixtures will still develop if ignored.
Determination of Soluble Salts in Chrysanthemum Soils -
Soluble salts are easily measured by mixing one part air-dry
soil to two parts water and reading on a Solu-Bridge at 25"C.
The Solu-Bridge is calibrated to read specific conductance from
10 to 1,000 mhos x 10-5 or 0.1 to 10 mhos x 10-3. Solu-Bridge
readings on two types of soil or potting media may be interpreted
as shown in Table 11. These interpretations are designed for
sandy soils and soil mixtures that will retain enough water to
equal 25% of their dry weight at field capacity and for soil
Table 11. Interpretation of Solu-bridge readings for 1:2 mixture of soil:water.
Types of soil Solu-Bridge Salt
or media reading rating Remarks
Sandy soil with 25% Below 25
water holding capacity (.25) *
Low Plants usually need
Soil mixtures with 50% Below 33 fertilizer.
water holding capacities (.33)
Sandy soil with 25% 25 to 50 Satisfactory for planting
water holding capacity (.25 to .50) Low to and growth when read-
medium ing in upper range, but
Soil mixtures with 50% 33 to 66 fertilizer may be applied
water holding capacities (.33 to .66) safely.
Sandy soil with 25% 50 to 100
water holding capacity (.5 to 1.0) Medium Desirable salt range, no
to high fertilizer needed.
Soil mixtures with 50% 66 to 130
water holding capacities (.66 to 1.30)
Sandy soil with 25% 100 to 150 Do not fertilize or allow
water holding capacity (1.0 to 1.5) Very soil to become dry, other-
high wise, salt damage may
Soil mixtures with 50% 130 to 200 result.
water holding capacities (1.3 to 2.0)
Sandy soil with 25% Above 150 If above 200 for sandy
water holding capacity (1.50) soils or 250 for soil mix-
Excessive tures, leach soil thor-
Soil mixtures with 50% Above 200 oughly.
water holding capacities (2.00)
*Numbers in parenthesis are for a Solu-Bridge calibrated in millimohs x 10-3 at 25oC.
mixtures that hold enough water to equal 50% of their dry
weight. Field capacity moisture is the amount of water remain-
ing in the soil after gravitational water has been drained down-
ward following a heavy irrigation or considerable rainfall. Solu-
Bridge readings may be converted to approximate ppm soluble
salts in the soil solution at field capacity moisture by multiplying
the Solu-Bridge readings by 40 for sandy soils that have ap-
proximately 25% water holding capacity or by 30 for the soil
mixtures with 50 % water holding capacity. If the Solu-Bridge
is calibrated in millimohs x 10-3, use factors 4000 and 3000 for
sandy and organic mixtures, respectively.
Determination of Salts in Irrigation Water The concen-
tration of soluble salts in water at 250C may be calculated by
multiplying the Solu-Bridge reading by 7 or by 700 if the Solu-
Bridge is calibrated in millimohs x 10-3.
PINCHING, PRUNING, AND DISBUDDING
Pinching consists of removing the growing terminal to per-
mit axillary buds to begin to grow or "break" and produce sev-
eral stems per plant. On single stem crops the plant population
is increased and pinching omitted.
The three types of pinches used in Florida are hard, soft,
and tip. The hard pinch consists of removing 2 inches or more
of the top growth and is used to secure additional cuttings. Dis-
advantages of the hard pinch are that subsequent breaks are
slow to develop from the hard tissue, and an additional 2 to 3
weeks of growing time is required to produce cuttings.
The soft pinch is made by removing the upper 1 to 1 inch
of terminal stem. This is the most commonly used method, is
easiest, and requires least labor. The tip pinch is made by re-
moving the growing point down to the first expanding leaves.
Care must be exercised to completely remove all the growing
point, or malformed growth will occur and the plant will need
Field and Bench Crops Since photoperiod is controlled for
commercial plantings, time to pinch is determined primarily by
temperature and variety. During the cool winter season 2 to 3
weeks are required between planting and pinching, and during
warm weather 1 to 2 weeks.
Potted Crops Pot mums are pinched for height control and
to produce more flowers per plant. Pot mums are classed into
three groups (short, medium, and tall), according to the natural
height of the variety. The short group should be pinched 1 to 2
weeks prior to initiation of short days, and the medium and tall
height groups from 1 to 11, weeks after short days are started.
The exact pinching time will vary with season as well as variety.
In general, more time prior to pinching is suggested for the cool
season crops and less time for the warm season and greenhouse
Sometimes pot mums are double pinched to give additional
blooms per plant; however, this requires an additional 2 to 3
weeks of growing time.
Pruning is the removal of extra side breaks developed from
the axillary buds after pinching. These extra shoots should be
removed to permit remaining shoots to develop into strong
stems. Care must be taken to avoid excessive damage to the
Field and bench crops are usually pruned 2 to 3 weeks after
pinching. The exact number of stems to leave per plant depends
upon spacing. When either single-flower or spray-flower groups
are set on 6 x 8 inch spacings in 4-foot beds, the inner rows are
usually pruned to 2 stems per plant and outer rows to 3 stems
per plant. Complete details on plant spacings are given in the
section on spacing and supporting.
Pot mums grown in Florida are not pruned, and all breaks
are allowed to develop. This gives a more compact plant, but
flower size may be reduced slightly over pruned pots.
The terminal bud of the spray-flower group is removed to
develop a spray of large uniform flowers from lateral buds.
Usually the upper 4 to 6 lateral buds develop. Removal of addi-
tional lower buds is desirable, but the labor requirement is so
great that it is not practical. If the terminal bud is not removed,
it will flower from 1 to 2 weeks ahead of lateral buds.
In the single-flower group, lateral buds are removed to allow
the terminal bud to develop into a large flower. Most varieties of
pot mums grown in Florida have lateral buds removed for at-
tractiveness, uniformity, and the development of large terminal
All disbudding should be done as soon as the buds can be
easily rolled out between thumb and forefinger. If disbudding
is attempted too early, the terminal bud or stem may be dam-
aged, and if buds are removed too late, flower quality will be
Chrysanthemum morifolium is classed as a short day plant;
it blooms when days are short and nights long. Actually, flower-
ing is controlled by length of the dark period, but the terms day-
length and photoperiod are more commonly used. Plants remain
vegetative and continue to grow without producing flowers as
long as the daylength is 141 hours or longer. When days are
shorter than 141/, hours, flower buds will be initiated, but days
must be 131) hours duration or less before flower buds develop.
Actual critical photoperiods vary somewhat between varieties,
but these are controlled with scheduling.
Complete control over flowering may be obtained by utilizing
either normal daylengths, lighting, black cloth, or a combina-
tion. Lighting is used when crops are to be maintained in the
vegetative state and normal daylength is less than the critical
photoperiod. On the other hand, black cloth is used when days are
longer than the critical photoperiod and flowering is desired.
Chrysanthemums will bloom during periods when natural
daylengths are shorter than the critical photoperiod. Artificial
lighting is necessary during these periods to produce proper
stem lengths and sufficient leaves to support normal flower crops.
Lighting Systems Cyclic and continuous lighting systems
are used in Florida, and some growers are testing quarzline
traveling light systems. At present, most production is still
under continuous lighting systems.
The amount of light that must be applied and duration de-
pends on type of system installed and light intensity. Actual
light levels obtained will vary with type of distribution system,
wire size, and length of runs; therefore, growers must measure
the light to be sure their systems are properly designed. Most
electric companies will provide light meters calibrated in foot
candles; or a low cost meter manufactured by General Electric
Company may be obtained. Light measurement should always
be made at the terminal growing point of the plant.
Factors affecting light levels include number and size of
bulbs, distance from light source, voltage, and type of reflector.
Light intensity decreases by the square of the distance from
the source; thus intensity may be increased by lowering lights
or increasing bulb size. If sufficient lights are available but
light levels too low, a voltage drop may be occurring. This prob-
lem may be caused by insufficient wire size for number of lights
installed or by too long a run. Poor or dirty reflectors or bulbs
may reduce the amount of light reaching the plants by 50%o or
more. Clean reflectors should be used unless newer type light
bulbs with built-in self-contained reflectors are available. Reflec-
tors are also useful in reducing percentage of broken bulbs when
lights are burning during rainfall.
Floral initiation will occur under lights when insufficient
light is provided to maintain the vegetative state, and an uneven
crop composed primarily of crown budded plants instead of
normal terminal buds will be produced. Crown buds are unde-
sirable in spray type chrysanthemums and are frequently un-
salable. A crown bud is a flower bud surrounded by vegetative
buds and characterized by strap-like leaves beneath the bud,
while a terminal bud is a flower bud surrounded by flower buds
with normal leaves beneath. Crown buds may occur where a
marginal lighting system is being used, especially during periods
of cool weather in outdoor production.
Continuous lighting utilizes a 3 to 4 hour light period during
the middle of the night to maintain plants in a vegetative state.
Usually 3 hours of light are sufficient to prevent flowering ex-
cept during November, December, and January when 4 hours
should be used. Light is provided between 10 p.m. and 2 a.m.
when 4 hours are used or between 10:30 and 1:30 when 3 hours
are used. Continuous lighting is more expensive to operate than
cyclic lighting, but provides more positive vegetative control
on all varieties.
In most growing operations, lighting systems are designed
to provide an average of 10 foot-candles of light at the plant's
growing point. Such systems may supply 5 foot-candles in the
darkest areas but are acceptable unless low temperatures occur.
However, best plant response is obtained where light levels are
maintained between 7 and 10 foot-candles at points most distant
from lights during the period of light utilization.
In field production approximately 10 foot-candles of light can
be obtained by using 150 watt reflectorized bulbs spaced 8 to 10
feet apart in rows 8 to 10 feet apart and 7 feet above the ground.
Similar spacing can be used in greenhouses where ground beds
and wide areas are treated. Where flowers are grown on raised
benches, approximately 10 foot-candles can he obtained by using
100 watt bulbs spaced 6 to 8 feet apart suspended 3 to 4 feet
above the crop. However, growers should remember that each
installation must be checked with a light meter before use to
ascertain that sufficient light is being obtained.
Cyclic or flash lighting is a system whereby lights are turned
on and off in cycles or flashes. The advantage over the continu-
ous lighting system is the savings obtained through use of less
electricity. However, cyclic lighting systems are more expensive
to install and maintain, and lighting programs are more critical
since little more than marginal amounts of light are applied.
Higher light intensities must be available than are used in the
continuous lighting system.
Recommendations are to use a 6 to 7 minute continuous light
period (cycle) during each 30 minutes period between 10 p.m.
and 2 a.m. Light intensity must be of 10 foot-candles at the
weakest point, or crown budding may occur on some varieties.
Since the lights are on for approximately 1/3 of the time, electric
cost is reduced.
In field production a minimum of 10 foot-candles of light
can be obtained by using 150 watt reflectorized bulbs spaced
6 to 8 feet apart in rows 8 feet apart where lights are suspended
about 7 feet above the ground. Similar spacing can be used over
greenhouse ground beds. In greenhouses where raised benches
are used, a minimum of 10 foot-candles can be obtained by
spacing 100 watt bulbs 6 feet apart 3 feet above the bench.
Quarzline lighting is a system that utilizes single traveling
lights of high intensity. Although the system is used in European
greenhouses, it has yet to be proved under Florida conditions.
Two growers who have tried this light system on field produc-
tion areas have encountered many difficulties.
Length of Light Period Required When lighting is neces-
sary, crops grown for different purposes should be lighted for
different periods of time to provide desired stem length. This
information can be found in the scheduling section.
Months to Light to Prevent Bud Set Actual daylength
response of different varieties varies, but generally lights are
necessary during the period from September 5th until April 10th
to keep chrysanthemums in a vegetative state. Actual dates may
differ slightly because of weather conditions, mainly dark or
cloudy weather, and growers who want to be sure they maintain
plants in a vegetative condition use lights from September 1
until April 15.
During spring and summer months, days are longer than
the critical photoperiod of 131' hours, and short photoperiods
are obtained by covering plants with black cloth to exclude light.
Most growers use a black sateen cloth which is adapted to field
and greenhouse production. Other materials such as black plastic
films and closely woven saran cloth have been used, but are less
satisfactory because they trap water and have a short life. Black
plastic has a short use period and is difficult to handle.
Black Cloth Systems Until recently all shade cloth was
manually pulled over chrysanthemum beds, but a recent move
toward mechanization and power application has revolutionized
Manual shading is still the primary method of applying shade
both in greenhouses and field production in Florida. When this
system is used supports are placed over the beds at 6 to 10-foot
intervals with three connecting wires running between supports.
Wires are placed at edges of supports and in the middle to pre-
vent cloth from damaging plants. Supports should be 4 feet in
height to prevent sagging cloth from coming in contact with
flower buds, because they are easily broken when small.
Black cloth is positioned on supports so it completely covers
the crop from ground level up.
Power shading is an innovation that has found application
in a number of greenhouse operations in various sections of
the country. The systems are best adapted to greenhouses where
clear spans of at least 20 feet can be obtained. Those systems
being utilized at present are components of greenhouse vent
systems, garage doors, or are completely grower-manufactured.
Growers who use power shading have been successful in de-
creasing labor costs and management problems. These systems
allow pulling of shade later in the day, which helps prevent heat
buildup under cloth during summer months. More complete in-
formation on power shading can be found in Chrysanthemum
Technical Bulletin No. 310 available from George J. Ball, Inc.,
West Chicago, Illinois.
Months to Black Cloth to Induce Bud Set Black cloth
should be used between the 10th of April and the 10th of Sep-
tember, when short-day cycles are desired. Varietal response
varies, but these dates have proved satisfactory under Florida
When to Pull Black Cloth Most growers prefer to pull
black cloth around 4:30 p.m. and after 8:00 a.m. when their
labor is available. This method, although acceptable in cool
regions, is not recommended in Florida because of heat buildup
beneath cloth. Therefore, growers should wait until about 7 p.m.
Eastern Daylight Time to pull cloth to prevent heat damage.
If labor is a problem, cloth may be pulled about 5 p.m., but sides
should be left up; then a single laborer can lower the sides about
7 p.m. In the morning cloth may be removed about 8 a.m. with-
out incurring problems from heat buildup. When cloth is re-
moved from over flowers in the morning, it should be pulled
back to prevent shading plants during daylight hours.
Scheduling or timing can be modified by temperature and
fertilization and is a real problem in field production.
Response Groups Commercial chrysanthemum varieties
sold today are divided into response groups, which is a designa-
tion of the number of weeks required from start of short days
until flowering. Response group listings have been established
under northern greenhouse conditions where reduced light levels
are normal during much of the growing season. Therefore, actual
flowering dates may be shortened under Florida conditions de-
pending on period of year, temperature, and light levels. As an
example, varieties in the 10-week response group flower in 9
weeks under greenhouse conditions and outdoors except during
cold weather periods. Tables 1-3 contain the response group
listing for several varieties grown in Florida.
Timing of Bloom Initiation of short days to obtain flowers
on specific dates varies with type of production.
Proper timing of field production chrysanthemums is difficult.
When single stem (non-pinch) crops are produced, long day-
lengths are given for approximately 4 weeks from the time
rooted cuttings are planted. When non-rooted cuttings are placed
in the field and grown single stem, they are lighted for 6 weeks.
When pinch crops are grown, 2 additional weeks of light are
required prior to starting short days. Normally, an additional
week of light is necessary for rooted and nonrooted cuttings set
during winter months.
Greenhouse production provides more positive control of
climatic factors, and therefore, a more precise control of flower-
ing. Single stem crops are lighted for 2 to 3 weeks; then short
days are initiated. Pinched crops are lighted for one week,
pinched, and lighted an additional 2 to 3 weeks before short
days are started.
Pot production presents a different problem, since short
rather than long stems are desired. In field production pots are
usually planted, lighted for 1 or 2 weeks, pinched, then short
days begun or plants are lighted for 1 additional week. On va-
rieties where tallness is a problem they may be lighted for one
week, grown under short days for a week, and then pinched.
Some growers also use a different schedule, lighting for a longer
period of time to produce larger plants and then using growth
retardants to obtain height control. In greenhouse pot produc-
tion plants are pinched when planted and short days begun; or
plants may be lighted for one or two weeks, then pinched, and
short days begun.
Climatic Effects on Timing Weather and time of year
have considerable effects on photoperiodic responses of chrys-
anthemums. Most low temperature problems are associated with
field production, while high temperature problems are associated
with field and greenhouse production areas.
When low temperatures of 50F or below occur during the
long-day period, 1 day should be added to the lighting schedule
for each night the temperature falls below 500F. This additional
lighting is necessary to obtain desired stem length. With many
varieties low temperature decreases short day requirement and
plants may form crown buds if the lighting system is marginal.
If this situation exists, additional lighting should be applied
nightly during those periods when night temperatures drop be-
If temperatures of 50'F occur during short-day treatment,
flowering date will be delayed 1 day for each night the tempera-
ture is 50F or below. Under field conditions this occurs fre-
quently during the winter growing season, and growers attempt
to compensate by adding a corresponding number of days to the
normal response group.
Freezing temperatures may occur in field production during
winter months which may intensify problems listed above;
however, the main problem is damage to growing tips, flower
buds, and stems. If freeze damage occurs to growing points in
an early growth stage while under long days, it can be treated
as a pinch and a new schedule initiated. Damage occurring after
short days are initiated cannot be overcome, and damaged plants
are usually flowered unless severely hurt. Damage to flower buds
may not be visible until flowering, because frequently only one
or two rows of petals are injured. Stem damage does not usually
cause serious injury to the crop, but stems may be short, hollow,
and weak, and may lack ability to take up water properly after
High temperatures affect chrysanthemums by causing a re-
duction in quality by reducing sugars (carbohydrates) within
the plant. Usually this condition is manifested in flowers and is
indicated by a reduction in size and petalage.
High temperatures can also cause a problem known as
"heat delay," when night temperatures are high during summer
months. Usually flowers come into bloom late and open unevenly
within a bed. The most critical time is when short days are
started, since high temperatures can partially counteract effects
of short daylength. The problem is best corrected by using only
good black cloth and preventing heat buildup beneath cloth.
INSECTS AND MITES4
Control of insect pests on chrysanthemums is always a prob-
lem in Florida, where insect populations are at a high level
throughout most of the year. In addition to using insecticides
and miticides, growers should control weeds and other undesir-
able brush growing close to greenhouses or field production
areas, as they may harbor insects which may move into produc-
tion areas. Growers should also keep shade-screening tight and
in good condition to reduce the numbers of insects that get into
Application of Pesticides
Pesticides should be applied while insects and mites are
small in size and few in number. This results in more effective
control and less injury to plants. Growers should inspect crops
frequently to determine the proper time to spray to prevent a
pest buildup. In many operations sprays are applied on a weekly
or more frequent preventive schedule. This practice is recom-
mended in a high value crop such as chrysanthemums, but does
not preclude the need to check plants frequently for possible
Methods of Application Mites and some insects are found
primarily on the lower leaf surface; therefore, sprays should
be applied so both leaf surfaces are covered with pesticides.
Many failures to control pests are the fault of application tech-
niques rather than of the pesticides.
'Additional information on pesticide use, safety, and other problems may be
found in "Florida Insect Control Guide."
When insecticide granules are used, they should be worked
into the top 4 to 6 inches of soil for best results. If granules are
applied to the soil surface after planting, follow with thorough
Application Equipment To obtain good insect control with
pesticide sprays, use a power sprayer with mechanical tank agi-
tation. Nozzles should be arranged to provide complete coverage
of both leaf surfaces, and sufficient pressure should be used to
penetrate heavy foliage in centers of beds. When granular ma-
terials are to be applied, the applicator should be accurately cali-
brated so the proper rate will be used.
Phytotoxicity or Plant In jury Sometimes a pesticide or pes-
ticide mixture may cause injury to chrysanthemums. Injury
often is correlated with temperature, humidity, or other environ-
mental factors. If a pesticide is known to cause injury some-
times, it should be applied during the coolest part of the day
and when plants are not deficient in water. Plants in partial
shade are less likely to be injured than those in full sun.
Wettable powder sprays are less likely to cause plant injury
than sprays of emulsifiable concentrates, but the former are
more likely to leave a visible residue on foliage or flowers. Dusts
may also be used and in some cases are preferable on open flow-
ers when damage may result from using sprays.
Although growers frequently apply insecticides and fungi-
cides together, plant injury is less likely to occur if they are
applied separately. Most basic materials are compatible, but
some formulations may be incompatible because of solvents and
emulsifiers. In general, liquids should be mixed with liquids and
wettable powders with wettable powders.
Human Toxicity Most pesticides are toxic to humans, and
care must be exercised in their use. Make sure laborers follow
label directions concerning protective clothing, goggles, and res-
pirators, especially when weather is hot and they have a tend-
ency to take off these protective devices.
Safety Precautions -
1. All insecticides are poisons, and safety precautions listed
on the container labels should be followed. Parathion,
Systox, Phosdrin, Thimet, and Di-Syston are especially
toxic and should be used only by properly trained and
2. Read the entire label, including small print, before open-
3. Store pesticides in original labeled containers out of
reach of children, irresponsible people, and pets, and
preferably under lock and key.
4. Dispose of left over spray materials and empty containers
promptly and safely.
5. Keep pesticides from getting into fish ponds, streams and
6. Avoid drift of pesticides to adjacent areas or to crops
that may be eaten by man or animals.
Aphids are soft-bodied greenish, yellowish or black sucking
insects usually less than 1/a-inch in length. They are commonly
found in colonies infesting new growth, which develops a curled,
crinkled appearance. When flower buds are attacked while in
the development stage, blooms will be stunted or deformed.
Aphids reproduce rapidly and should be controlled before
populations build up to high numbers.
The corn earworm and related species are very destructive
to chrysanthemums, especially standards, since they feed on
flower buds and petals of open flowers. Young plants may also
be attacked and large amounts of foliage consumed before con-
trol can be obtained.
These caterpillars may range in color from light green to
dark brown with light or dark longitudinal stripes. They are
especially troublesome during spring or fall months when they
may build up to high numbers in nearby abandoned vegetable
Cutworms are usually associated with plants severed at the
soil line, but in some species attack foliage. Most cutworms are
brownish with a lighter or darker stripe, but colors and mark-
ings vary considerably, although all are caterpillars 1 to 2
Leaf miners are especially troublesome in field production.
The larval or maggot stage of this insect is commonly found
tunneling within leaves and is readily visible, while the adult
fly, although present, is rarely noticed. Injury to foliage causes
it to be unsightly and decreases market value. If injury becomes
serious, some leaf drop may also occur.
Larvae are yellowish white, about 1/10 inch long, and make
tunnels within leaves that are long and winding or blotch like;
hence the common names of serpentine and blotch leaf miners.
Adults of serpentine leaf miners are small blackish flies some-
times marked with yellow.
Loopers are the larval or caterpillar stage of moths that
damage chrysanthemums by eating holes in young leaves and
may, as they grow larger, damage the growing point. Color of
these insects varies considerably, since any one of many types
of loopers may be present at one time. Control is best obtained
while loopers are small, as they are much more difficult to kill
as they increase in size.
Mealybugs are soft bodied, sucking insects covered with a
yellowish or whitish wax-like material. These insects injure
chrysanthemums by feeding on sap and depositing unsightly
egg sacks on foliage and stems. High populations may discolor
stems and leaves and deform leaves.
Mites provide a serious pest control problem to chrysanthe-
mum growers. A number of different mites including the two-
spotted spider mite attack mums. All produce the same symp-
toms which include, in the initial stage, pale green mottling on
upper leaf surfaces, and in later stages, bleaching of chlorophyll
from leaves, curling, and leaf drop. Mites are very small, and
their habit of feeding on the underside of foliage makes them
difficult to see.
Mites are soft-bodied, are about 1/50th of an inch in length,
and vary in color from greenish to yellowish and reddish. Mites
may also have dark spots on either side. Reproduction is rapid,
and a single female may have over a million descendants in a
month at a temperature above 70'F.
Control of mites is difficult, because some have become re-
sistant to certain pesticides. Preventive sprays should be applied
from planting until harvest.
Tarnished plant bug is not difficult to control, but is fre-
quently found in field production areas. This insect feeds on
foliage, causing small grayish dead areas, and may also be indi-
cated by wilting of leaf tips.
The tarnished plant bug is a sucking insect about 1/4 inch in
length and generally brown in color. A distinguishing mark is
a clear yellow triangle with a round black dot at the tip near the
back of the body on the wings.
Thrips infest foliage, developing buds, and open flowers pri-
marily during spring months. Foliage may develop a silvery ap-
pearance from their feeding, but the most serious problem is
browning of flower petals. During hot dry weather in the spring
large numbers may migrate into greenhouses or field operations
and cause serious damage to open flowers.
Table 12. Pest control suggestions for Florida-grown chrysanthemums.
Pest Control material Formulation Rate per 100 gal. Remarks
Aphids Diazinon 50% WP 1 lb. Some aphids are resistant to diazinon.
Di-Syston 10% granular 3 to 41/ lbs. A systemic insecticide apply carefully with
per 1000 sq. ft. properly calibrated equipment.
Meta-Systox-R 2E (2lb./gal.) 11/ pt. A systemic insecticide, may injure open flowers
of iceberg and some other varieties, especially in
Parathion 15% WP 2 to 3 Ib. Do not spray on open flowers. Very toxic to
humans. Use V rate in greenhouses.
Thimet 10% granular 3 to 4%1/ lbs. A systemic insecticide, apply carefully with prop-
per 1000 sq. ft. erly calibrated equipment.
Thiodan 50% WP 1 to 2 lbs. Do not spray on open flowers.
Corn Earworm DDT 50% WP 2 lbs. Do not spray open flowers.
5% dust 1 lb./1000 sq. ft.
DDT + Parathion 50% WP + 15% WP 2 lb. + 1 lb. Do not spray open flowers. Use 1z rate in green-
Dieldrin 50% WP 1 Ib. May be used after buds show color.
Sevin 80% WP 1!4 lb. May injure bluechip, iceberg, and some other
Cutworms Chlordane 40% WP 21/2 lb. Soil application.
10% granules 1 lb./1000 sq. ft.
8E 1 pint
Dieldrin 50% WP 1 lb. Soil application or spray.
1.5 E 1 Qt.
Sevin 80% WP 1 4 to 2 lbs. See under corn earworm.
Grasshopper Chlordane 40% WP 21/ lb. Spray outside crop area as well as crop.
Dieldrin 50% WP 1 lb. Spray outside crop area as well as crop.
Pest Control material Formulation Rate per 100 gal. Remarks
Leafhoppers DDT 50% WP 2 lb. See under corn earworm.
Meta-Systox-R 2 E 1%' pt. See under aphids.
Parathion 15% WP 2 to 3 lbs. See under aphids.
Leaf Miners Diazinon 50% WP 1lb. Emulsifiable formulation may injure some vari-
Di-Syston 10% granular 3 to 4% lbs. See under aphids.
per 1000 sq. ft.
Guthion 25% WP 2 lbs. Use emulsifiable material with care.
Meta-Systox-R 2 E 1/ pt. See under aphids.
Thimet (Phorate) 10,; granular 3 to 412 lbs. See under aphids.
per 1000 sq. ft.
SLeaf Tiers DDT 50% W P 2 lbs. See under aphids.
Parathion 15% WP 2 to 3 lbs. See under aphids.
Sevin 80% WP 1i lbs. See under corn earworm.
Loopers Bacillus WP 3 lbs. + 1 oz. Apply weekly on a preventive program.
thuringiensis Triton X-100
aqueous suspension 2 qts.
Phosdrin 2 E 1 qt. Extremely toxic to humans.
Thiodan + DDT 50% WP + 50% WP 1 lb. + 2 lbs. Do not spray on open flowers.
Mealybugs Parathion 15% WP 2 3 lbs. See under aphids. A wetting agent may be neces-
Diazinon 50% WP 11/ lbs. A wetting agent may be necessary.
Table 12. Pest control suggestions for Florida-grown chrysanthemums (continued).
Pest Control material Formulation Rate per 100 gal. Remarks
Mites Aramite 15% WP 2 lbs. Do not use emulsifiable material.
Kelthane 18.5% WP 2 lbs. Not effective on resistant mites.
Morestan 25% WP lb. May cause injury on open flowers.
Pentac 50% WP %4 lb. More effective during cooler months.
Tedion 25% WP 1 lb. Use at 2-week intervals slow acting.
Spittle Bugs Dieldrin 50% WP 1 lb.
Lindane 25% WP ilb.
Thiodane 50% WP 1 lb. See under aphids.
Tarnished Dieldrin 50% WP 1 lb.
t. Plant Bugs
DDT 50% WP 2 lbs. Provides good control see under corn earworm.
Thrips DDT 50% WP 2 Ibs. See under corn earworm.
Dieldrin 50% WP 1 lb. Can be used on open flowers.
Lindane 25% WP 1 lb.
Meta-Systox-R 2 E 11/2 pt. See under aphids.
Parathion 15% WP 2 to 3 lbs. See under aphids.
White Flies Parathion 15% WP 2 to 3 Ibs. See under aphids.
Diazinon 50% WP 1 lb.
Thiodan 50% WP 1 lb. See under aphids.
Meta-Systox-R 2 E 11/ pt. See under aphids.
Thrips are small slender sucking insects just visible to the
eye. Adults are brownish or yellowish with wings and are
capable of flying.
Other insects of lesser importance include grasshoppers,
sowbugs, leaf tiers, leafhoppers, spittle bugs, and white flies.
Control materials for the insects described are listed in
Chrysanthemum diseases can be divided into three general
groups according to causal agents: fungi, bacteria, or viruses.
Descriptions, photographs, and control measures for chrysanthe-
mum diseases are presented in Florida Agricultural Experiment
Station Bulletin 637A, 1966, "Chrysanthemum diseases in Flor-
ida"; therefore, only a summary of this information is presented
Bacterial and Fungal Diseases
A summary of the most common diseases caused by fungi and
bacteria is presented in Table 13, and the chemical control meas-
ures are presented in schedules A through E (pages 57-59). In
addition to chemical sprays proper soil fumigation, strict sani-
tation practices, and use of indexed cuttings will greatly reduce
Viruses occasionally affect chrysanthemums in Florida, but
they are not of major concern due to excellent virus indexing
programs used by commercial propagators. Viruses are usually
transmitted during pinching or by insects. Recommended con-
trol practices include use of virus-indexed cuttings, disease-free
stock, and maintenance of excellent insect control, especially for
aphids, leaf hoppers, and thrips.
Fungicides recommended for most leaf and flower diseases
are effective in preventing germination of spores or killing newly
germinated spores. Fungicides should be applied often enough
to maintain a protective residue on leaves and flowers once
"Adapted from "Chrysanthemum diseases in Florida." Fla. Agr. Exp. Sta.
Bul. 637A, 1966, by C. R. Jackson, L. A. McFadden, R. O. Magie, and
A. J. Overman.
Table 13 Summary of principal chrysanthemum diseases in Florida.
Disease Plant parts affected Methods of distribution* favoring spreading
Ascochyta blight Bracts, petals, flower stalk, leaves, Soil, stock plants, splash- Wind, water, wet weather.
(Ascochyta chrysanthemi) stems. One-sided distorted growth. ing water, wind, cultural Most common October to
procedures, compost. April.
Botrytis blight Flowers, leaves, stems. Gray (velvety) Stock plants, rooting beds, Cool temperature, high ni-
(Botrytis cinerea) spore masses present after moist con- splashing water, wind, cul- trogen fertilization, rain.
editions. tural procedures. December to April.
Septoria leaf spot Leaves. Starts on lower foliage and Soil, splashing water, Wind and water, wet
(Septoria obesa and S. progresses upward, wind. weather. September to
Stemphylium ray speck Older flower petals and leaves. Wind, splashing water. Wind, water, and high
(Stemphylium floridanum) temperatures. March to
Pythium stem rot Stems and leaf petioles, roots. Plants Soil, rooting bed, surface High soil moisture and
(Phythium aphanidermatum) wilt quickly; stems blackened. water, splashing water, temperatures. March to
S Rhizoctonia stem rot Base of stem rots ("wirestem"); Soil, rooting bed, surface High soil moisture. Pres-
(Rhizoctonia solani) plants wilt slowly, water, compost. ent year around.
Cottony stem blight Stems. White to black hard clumps of Soil, wind, compost. Cool temperature, and
(Sclerotinia sclerotiorum) mycelium on and in stems. Plants wilt. wind. December to March.
Southern Blight Base of stem. Collar of soil adheres Soil, wind, compost. High temperature and a
(Sclerotium rolfsii) to stem. Plants wilt. moist, well-aerated soil.
Fusarium stem rot Stems decayed with brown streaks Soil, stock plants, surface High nitrogen fertiliza-
(Fusarium oxysporum) extending upward. Plants wilt at time water, splashing water, tion and warm tempera-
of flowering, compost. tures. Warm weather.
Verticillium wilt Plants wilt, turn yellow, or just grow Soil, stock plants, cutting, Cool weather. Cool soil.
(Verticillium spp.) poorly. Leaves die from base to top of surface water, equipment,
plant. Frequently one-sided growth, wind, compost.
Bacterial blight Stems and leaves. Rooted cuttings. Stock plants, rooting bed, High temperature and
(Erwinia chrysanthemi) Yellowish pith; hollow stem. splashing water, cultural moisture. March to No-
Bacterial leaf spot Flower buds, upper flower stalk, and Stock plants, rooting bed, Excessive rainfall. March
(Pseudomonas cichorii) leaves, splashing water, to October.
*Man, animals, tools, posts, plant debris, and mobile equipment are frequent carriers of disease organisms to clean areas.
weekly on foliage and twice weekly on open flowers. During
rainy weather or periods of frequent overhead irrigation, more
frequent applications may be needed.
Schedule A Fungicides for control of leaf diseases caused
by Septoria, Ascochyta, and Botrytis fungi. Use any one of the
following chemicals. Amounts per gallons of spray are: [
1. Maneb (80%) 1 pound. __
2. Maneb with zinc (sold as Manzate D and Dithane M-22
Special) 1 pound.
3. Dithane M-45 1 pound.
4. Maneb (80%) + captain (50%) -1/ + % pound.
5. Zineb (75%) + captain (50%) 1/ + %/ pound.
6. Zineb (75%) 1 pound.
7. Captan (50%) + ferbam (76%) 1 + 8 pound.
8. Captan (50%) 11/2 pound.
9. Botran (dichloran, 50%) 1 pound.
10. Morsodren or Panogen Turf Fungicide (2.2% methyl
mercury dicyandiamide) liquid 1/4 pint.
These fungicides are not listed in order of preference. Maneb
and zineb should be used sparingly when Botrytis is a problem.
Schedule B Fungicides for control of flower diseases caused
by Ascochyta, Botrytis and Stephylium fungi. Use any one of
the following chemicals. Amounts per 100 gallons of spray are:
1. Captan (50%) 1 pound per 100 gallons as a spray.
2. Botran (50%) 2/3 pound per 100 gallons as a spray;
not to be mixed with other pesticides.
3. Captain wettable powder (50%) applied as a dust at 11/.
to 21/ ounces per 1000 square feet of bed area.
4. Zineb wettable powder (75%) applied as a dust at 3% to
11/ ounces per 1000 square feet of bed area.
5. Botran (dichloran) wettable powder (50%) applied as
a dust at %3 to 11 ounces per 1000 square feet of bed
6. Morsodren or Panogen Turf Fungicide liquid at 3 to 4
ounces per 100 gallons as an inexpensive, non-staining
7. Tutane (2-aminobutane carbonated, 26%) applied on wet
flowers as a spray at the rate of 4 ounces per 1 gallon of
water per 1000 square feet of bed area.
8. Tutane applied on dry flowers as a spray at rate of 6
ounces per 2 gallons of water per 1000 square feet of bed
9. Tutane at 3 ounces per gallon applied as a spray on cut
flowers wet or dry. Allow flowers to dry off before pack-
10. Tutane at 1 or 2 ounces per gallon used as a flower dip.
Dry off before packing.
Botran is effective against Botrytis but not against Ascochyta
and Stemphylium fungi. Botran should not be mixed with other
pesticides or spreaders. Suggestions for use of Tutane and Mors-
odren may have to be modified for some varieties. Tutane is not
compatible with some pesticides.
Schedule C Control of bacterial leaf spot. On susceptible
varieties spray once each day before irrigating (during 10 days
after planting) with Panogen Turf Fungicide or Morsodren at
3 ounces per 100 gallons of water. One spray per week on sus-
ceptible varieties during rainy weather is suggested thereafter.
Tribasic copper sulfate at 3 pounds per 100 gallons may be used
at weekly intervals but is injurious to many varieties. Discon-
tinue the above sprays during cool, dry weather.
Schedule D Fungicidal treatments for control of Pythi.tm
1. Where experience indicates that susceptible varieties are
attacked during warm, wet weather in spite of soil sterili-
zation, drench the soil with 4 ounces of Dexon-35W per 50
gallons of water per 400 square feet of planted area. Ap-
ply 1 to 3 days after rooted cuttings of 'Icebergs' and
other susceptible varieties are planted during summer or
early fall. Only one application is usually required if ap-
plied early enough. Apply Dexon immediately after mix-
ing in water.
2. For spot treatment of soil after removal of diseased plants
and debris, use 6 ounces of Dexon 35W per 25 gallons of
water and drench 1 quart per square foot of bed area.
3. To control the spread of Pythium infection during the
pinching of terminal buds on small plants, immediately
after pinching spray plants with 4 ounces of Dexon 35W
per 50 gallons of water.
4. When both Pythium and Rhizoctonia diseases (see Sched-
ule E) are present, Dexon 35W may be safely mixed with
Terraclor for application as a drench.
Schedule E-Fungicides for Rhizoctonia and southern blight.
1. Terraclor (75W) or equivalent form of PCNB (penta-
chloronitrobenzene) 1/, pound in 50 gallons of water
applied to 400 square feet of bed as a drench. Use on
established plantings or as a spot treatment in flowering
or rooting beds. Rinse foliage after application of drench.
For the control of foliar infection, spray both sides of
leaves with 1,4 pound Terraclor (75W) per 100 gallons
of water. More than 1 or 2 sprayings of Terraclor on the
same plants is not recommended. The toxicity of Terraclor
to many varieties is not known.
2. Panogen Turf Fungicide or Morsodren suggested for
spot treatment in the area where diseased plants are re-
moved. Apply as a drench, using 1 teaspoonful in 6 gal-
lons of water and 1 pint of solution per square foot; then
rinse foliage with water.
HARVESTING, PACKAGING, STORING AND
Standard chrysanthemums are cut when fully open, but be-
fore center petals have matured fully or lost all their greenish
color. Spray-flower chrysanthemums are cut when flowers of
the top 3 or 4 lateral buds are open, but before center petals
have completely expanded or lost their greenish color. At this
time flowers from other lateral buds will be starting to unfold.
Cutting experience with several varieties is required in order
to obtain the longest potential vase-life. Stems of both flower
types should be cut 36 to 40 inches in length and placed into
tall buckets containing a floral preservative. Otherwise, they
must be packaged immediately to avoid excessive dehydration.
Potted mums are ready for shipment to distant markets as
soon as flower petals begin to unfold but before flowers are
fully open. For local sales mature flowers are more desirable.
Cut-Flowers Prior to packaging, chrysanthemum stems
are cut to approximately 30 inches in length and the lower one-
third of the leaves removed. Spray chrysanthemums are bundled
in bunches containing 5 to 8 stems weighing about 14 ounces.
A paper or polyethylene sleeve is placed around each bunch to
compress flowers and help reduce water loss. Single flower
chrysanthemums may be packaged into small bunches similar
to spray flowers or packed individually with about 6 dozen per
box. Waxed paper is usually placed between flower heads to
reduce crushing and tangling.
Cut-flowers should be hardened for at least 12 to 24 hours
prior to boxing by placing stems in warm solutions (100-
1100F) containing a floral preservative. The temperature of
the hardening room should be below 700F. If the chrysanthe-
mums are not shipped within 24 hours, stems should be placed
in good quality water without a floral preservative.
Cut-flowers are boxed in rectangular paper boxes lined with
paper or polythylene (Figure 17). Flower heads are placed at
each end of the box and stems anchored in the middle with a
wood brace. The liner helps prevent bruising and reduced de-
hydration in transit. Moisture loss is retarded greatly with the
polyethylene liner, but completely air-tight liners cause moisture
to condense on flowers and Botrytis rot may develop in transit.
Therefore, if polyethylene liners are used, they should be per-
forated to allow some moisture loss.
Potted Mums Potted mums are packaged by placing a
paper or polyethylene sleeve around each plant which com-
presses and protects the plant in transit. Then pots are placed
upright in carboard boxes usually containing 6 pots per box.
Wet Storage Temperature and moisture are important
factors affecting subsequent vase life of cut-flowers. Chrys-
anthemums may be stored for 5 to 10 days at 35 to 500F pro-
viding stems are placed in water. Cold storage conserves food
materials (carbohydrates and sugars) by reducing the respira-
Prior to storage all surface moisture should be removed to
reduce possibilities of Botrytis rot in storage. Moisture may be
removed during hardening by use of infrared heat lamps or
circulating fans. Chrysanthemums should not be stored in large
or tightly wrapped bunches, since this encourages Botrytis de-
velopment. Hazards from Botrytis rot can be reduced by using
shallow trays with woven wire tops and loose flower bundles in
storage to permit adequate air circulation.
Dry storage at 31F Mastalerz6 reported that chrysan-
themums may be stored satisfactorily in low-temperature dry
storage for 30 days. For successful storage the temperature must
be maintained at 310F and flowers stored dry in moisture proof
containers which are permeable to toxic gases that may accumu-
late. At this temperature the respiration rate is greatly reduced
OJohn W. Mastalerz. 1963. Long term cold storage of cut flowers. Living
flowers that last. A National Symposium. Univ. of Missouri Dept. of Horti-
Figure 17. Chrysanthemums being packed for shipment.
and stored food materials (carbohydrates and sugars) are con-
served. Accurate temperature control (- 1F) and air circula-
tion in storage are essential to prevent cold spots and freezing
Moisture-proof containers are necessary to prevent dehy-
dration of tissue by the refrigeration equipment. Containers
should be covered with polyethylene which will permit toxic
gases to escape but still maintain moisture levels.
Special precautions should be taken to avoid storage of
flowers infested with Botrytis fungus. Most chrysanthemums
grown in the field from December through April are exposed to
Botrytis spores; therefore, when these flowers are stored, special
attention must be paid to Botrytis control pre- and post-harvest.
After low-temperature dry storage, flowers should be hard-
ened in a room at 50F for 12 to 24 hours before shipment by
recutting the stem and placing in 1000-110'F water containing
Storing Pot Mums Pot mums may be stored up to 2 weeks
when near maturity without sacrificing quality. Plants may be
held 4 to 5 days by placing them in a cool shaded area of the
saran house or for 1 week at 45 to 550F and up to 2 weeks at
Storage in light is superior to dark storage, especially at high
temperatures. Light prevents foliage from becoming depleted
of soluble food materials.
Pots should be watered prior to and during storage as neces-
sary to prevent excessive dehydration. Pot mums should not be
stored with wet foliage or stored in moisture-proof containers;
otherwise, Botrytis diseases may damage plants.
Lighting in Storage Recent research has shown that the
vase life of cut chrysanthemums can be increased greatly if they
are exposed to light.7 8 Illumination enables leaves to maintain
their photosynthetic capacity, chlorophyll content, and supply of
food sources, which in turn extends vase life. Beneficial effects
of light increase as the intensity is increased from 50 to 400 foot
candles; however, the higher light intensities may cause wilting.
Cut chrysanthemums receiving light at room temperature
were maintained 3 times as long as those in the dark. At 450F,
longevity of leaves was increased 34% compared to those in the
dark. Refrigeration conserved the initial supply of food materials
in the cut-flowers, and lighting in cold storage permitted photo-
synthetic processes to gain in food reserves over respiratory
losses. Intensities of 100 to 200 foot-candles of lights are sug-
gested for trials in cold storage.
Chrysanthemums are shipped from Florida by air, rail, and
truck. Transit temperatures as well as duration in transit grossly
affect keeping quality. Cross country shipping studies by the
'S. S. Woltz. 1965. Photosynthesis in chrysanthemum cut-flowers. Proc. Fla.
State Hort. Soc. 78: 415-417.
"S. S. Woltz and W. E. Waters. 1967. Effects of storage, lighting and tem-
perature on metabolism and keeping quality of Chrysanthemum morifolium
cut flowers relative to N fertilization. Proc. Am. Soc. Hort. Sci 91: 633-644.
USDA9 showed that shelf life could be reduced 50 % or more
by high transit temperatures. Poor refrigeration before loading
at transfer points, and at terminal markets was common to all
three modes of transportation.
Recent research in Floridao1 has shown that refrigeration
preserves both chlorophyll and soluble sugars in the leaves and
flowers by reducing the respiration rate, which in turn extends
Chrysanthemums generally may be shipped for up to 1 week
at 40F, 2 to 3 days at 500F,-and 1 day at 750F. Time in transit
should be as short as possible, especially at the higher tempera-
tures. Long warm periods during transit should be avoided.
Preservatives Preservatives are beneficial to chrysan-
themums if used properly. Research has demonstrated that
continuous exposure of chrysanthemum stems to certain pre-
servatives is detrimental to the foliage, although flowers will
continue to develop without damage. Where foliage is an im-
portant consideration, exposure of chrysanthemum to preserv-
atives for only 12 to 24 hours immediately after harvest is
recommended. Continuous use of a preservative is suggested
only where the flower alone is to be used.
Containers Holding containers should be cleaned with a
bactericide such as chlorox, and water should be changed fre-
quently. Continuous use of a dilute concentration of a bacteri-
cide in the water reduces stem clogging and enhances water
uptake without harmful effects to foliage.
Water Quality Recent research has demonstrated that
quality of water (salinity) used as holding solutions exerts
major effects upon the vase-life of chrysanthemums."1 When
chrysanthemum stems were placed in different well waters for
1 days, 5 days, or continuously, the vase-life of the foliage was
reduced as much as 20, 40, and 60% respectively, depending
upon the salt content of the well waters. Total salt content in-
"J. M. Uota Harvey, R. H. Segall, J. M. Lutz, M. J. Ceponis, and H. B.
Johnson. 1962. Transit temperatures of cut flowers shipped from Cali-
fornia. USDA AMS 459.
"1S. S. Woltz and W. E. Waters. 1967. Effects of storage, lighting, and tem-
perature on metabolism and keeping quality of Chrysanthemum morifolium
cut-flowers relative to N fertilization. Proc. Am. Soc. Hort. Sci. 91: 633-644.
"'W. E. Waters, 1968. Relationship of Water Salinity and Fluorides to Keep-
ing Quality of Chrysanthemum and Gladiolus Cut-Flowers. Proc. Am. Soc.
Hort. Sci. 92:633-640.
stead of specific salts in the water was the major contributing
factor to poor keeping quality. For each 100 ppm total soluble
salts in the holding solution the expected vase-life of the foliage
was decreased by one-half day if exposed continuously.
Vase-life of flowers decreased as water salinity increased,
but flowers usually lasted 4 to 6 days longer than foliage.
Well waters containing less than 500 ppm total soluble salts
are recommended for holding solutions for chrysanthemums.
Adjust water temperature to 1000 to 110'F before placing
stems in the water. About 1/ inch of stem should be clipped off
when solutions are changed or when the flowers are placed in
water after storage or shipment.
Nutrition and Keeping Quality Numerous experiments
have shown that pre-harvest nutrition exerts major effects on
the vase life of chrysanthemum cut-flowers. Luxurious nitrogen
fertilization reduces keeping quality as well as increases pre-
and post-harvest plant susceptibility to Botrytis disease. Nitro-
gen fertilization should be decreased the latter part of the grow-
ing season to increase keeping quality and decrease severity of
Botrytis rot. Laboratory analyses have shown that crysanthe-
mums receiving high nitrogen fertilization contain more nitro-
genous organic compounds and less soluble carbohydrates (food
sources) than those receiving less nitrogen fertilizer. Therefore,
for optimum vase-life nitrogen fertilization must be controlled
closely. (See fertilizer sections for programs.)
The authors wish to express their appreciation to (1) Drs.
A. M. Kofranek and 0. R. Lunt, University of California, for
figures 12, 14, and 16; (2) Dr. S. S. Woltz, University of Flor-
ida, for figures 8, 10, 11, and 15; (3) Mrs. A. J. Overman for
technical assistance; and (4) Dr. J. N. Joiner for figure 9 and
The use of trade names in this publication is solely for the purpose of
providing specific information. It is not a guarantee or warranty of the
products named and does not signify that they are approved to the ex-
clusion of others of suitable composition.