Group Title: Circular Florida Cooperative Extension Service
Title: Florida blueberry handbook
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 Material Information
Title: Florida blueberry handbook
Series Title: Circular Florida Cooperative Extension Service
Physical Description: 15 p. : ill. ; 28 cm.
Language: English
Creator: Lyrene, P. M ( Paul Magnus )
Crocker, T. E
Florida Cooperative Extension Service
Publisher: Florida Cooperataive Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1984?
Subject: Blueberries -- Florida   ( lcsh )
Genre: non-fiction   ( marcgt )
Statement of Responsibility: P.M. Lyrene and T.E. Crocker.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00014476
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltqf - AAA6880
ltuf - AJF8205
oclc - 20727077
alephbibnum - 001745424

Full Text

florida Blueberry

L.M. Lyrepe aild T.E. Crocker

Florida Cooperative Extension Service
Institute of Food and Agricultural Sciences
SUniversity of Florida, Gainesville
John T. Woeste, Dean for Extension

C23(o C-'

P. M. Lyrene is an Associate Professor of Horticulture, Research; and T. E. Crocker is a Professor and Extension Deciduous
Fruit Specialist, Fruit Crops Department, IFAS, University of Florida, Gainesville.


P.M. Lyrene and T.E. Crocker

Since 1920, blueberry culture in the United
States has increased from almost nothing to a major
agricultural industry. This growth has been largely
due to the release of improved cultivars, the first
of which were adapted to the northern United
States. These cultivars formed the basis of a new
fruit industry which has grown as better varieties
were developed and more growers became familiar
with blueberry culture. Today, about 30,000 acres
of cultivated blueberries are grown in the United
States, primarily in New Jersey, Michigan, and
North Carolina.
The success of blueberry cultivation in the north-
ern states has stimulated blueberry trials in other
parts of the country. In Florida, Georgia, and other
southeastern states, rabbiteye blueberries have
shown much promise. The rabbiteye is a southern
blueberry, and differs in several ways from the
highbush blueberries grown farther north. The ber-
ries themselves, however, closely resemble those
of the highbush, and the two are essentially indistin-
guishable in the marketplace. The high plant vigor
and high yields of rabbiteye blueberries have en-
couraged widespread plantings in Florida, -and it
appears that a sizable blueberry industry is develop-
ing in the state.
This handbook summarizes for growers and po-
tential growers what is currently known about grow-
ing blueberries in Florida. As with most new enter-
prises, much is unknown, but the oldest plantings
of improved blueberries in Florida are now 25 years
old, and much valuable information has been ob-
tained by the pioneering growers who established
them. In addition, improved cultivars and cultural
information have come from research on blueberries
which began at the University of Florida in 1950.
Additional information is available from university
research and grower experience in North Carolina,
Georgia, Arkansas, Michigan, and New Jersey, and
from U.S. Department of Agriculture blueberry
research. Information from all of these sources is
used in this report. The best procedures for growing
blueberries in Florida are still being worked out
and serious growers should keep informed on the
latest developments through the Florida Blueberry
Growers Association and through their county

The Outlook for Florida Blueberries
Blueberry plantings can range in size from a few
plants in the dooryard to a large commercial planta-
tion covering many acres. The needs of the plants

are the same in both cases. Although this handbook
was prepared with commercial plantations in mind,
much of the information is also relevant to dooryard
The profitability of blueberry plantations in
Florida depends on site selection, cultivar selection,
cultural procedures, and method of marketing.
Well-planned and well-managed blueberry farms
can be quite profitable in Florida. Production costs
per pound of berries here compare favorably with
those in other areas of the country where good
growers have made good profits. The cost of good
blueberry land in north Florida compares favorably
with that in the major blueberry states of Michigan
and New Jersey, and Florida plantations reach peak
production sooner because of longer growing sea-
sons. In Arkansas, a profitable blueberry industry
has been established during the past two decades
on soils that are inherently less suitable for
blueberry culture than many soils in Florida. Well-
managed blueberry farms established in Florida
during the last 20 years are doing well, further
demonstrating the profitability of Florida blueber-
Marketing Florida Blueberries
The method of marketing should be the first
consideration in planning a Florida blueberry farm.
Of the approximately 500 acres of blueberries cur-
rently in Florida, most are sold on the farm with
the customer picking the fruit (you-pick farm). To

Rabbiteye blueberries may be harvested by hand or by use of
various harvesting machines.

be successful with a blueberry you-pick farm, a
grower must enjoy working with people and must
be located in an area where potential customers are
available and where the market for you-pick
blueberries is not likely to be oversupplied within
the near future. In many parts of Florida where
blueberries can be grown, the you-pick market is
still almost untapped. Information is available from
the Extension service on how to establish and run
a you-pick farm. Diversified you-pick farms, on
which several different crops are produced, are
often the most successful.
Only recently have blueberry farms been estab-
lished in Florida for markets other than you-pick.
These are not yet in full production, and the most
profitable way to market the fruit has not yet been
determined. One alternative used by the 8000-acre
New Jersey industry is hand picking into pint con-
tainers for the fresh market. This requires large
amounts of reliable labor.
Mechanical harvest of blueberries is also possible.
A large machine can pick about 5 acres per day.
Mechanically-harvested blueberries can be sold on
the fresh market after cleaning and sorting, but this
requires a well-adjusted machine, a skillful
operator, proper timing of harvest, and suitable
cultivars. Not all the blueberies on a plant can be
picked on a single date because not all ripen to-
gether. Growers may choose to hand harvest the
earliest ripening berries and machine harvest the
Most of the large Michigan blueberry crop is
mechanically harvested for processing as frozen or
canned fruit. An explosion drying process for
blueberries has been developed and is being tested
in Georgia.
A first goal of the Florida blueberry industry
should be to supply fresh blueberries for Florida
markets. At present, some fresh-pack blueberries
enter the state from Georgia, New Jersey, and
Michigan, but the market is not adequately supplied
from these sources.
An important consideration in the possible export
of fresh Florida blueberries to other states is season
of availability from Florida compared to other im-
portant blueberry production area. The first
blueberries from early cultivars are picked about
May 15 in North Carolina, June 15 in New Jersey,
and July 10 in southern Michigan. It might be
expected that Florida blueberries would be earlier
than all of these, but the rabbiteye blueberry is
naturally a late ripener. When rabbiteye cultivars
are grown in the same field with early highbush,
the rabbiteyes ripen a full month later. Thus, the
first shipment of early rabbiteyes from Gainesville,

Florida would be about June 5 in an average year
with current cultivars. This would overlap the sec-
ond half of the North Carolina highbush harvest,
but would precede the larger New Jersey harvest.
Because the North Carolina blueberry industry is
relatively small (3000 producing acres compared to
8000 for New Jersey and 10,000 for Michigan), the
first half of June is still a good season for shipping
fresh blueberries. Eventually, a May shipping sea-
son will be possible in Florida as earlier ripening
rabbiteye cultivars and disease-resistant highbush
cultivars are developed for Florida. Earlier ripening
will become increasingly important in Florida as
Georgia and other southeastern states become major
blueberry producers.

Costs and Return for Blueberry Farms in
Several independent cost-and-return analyses
have been made for rabbiteye blueberries in the
southeastern United States, and all reach the same
general conclusions. The first is that starting a
blueberry farm is very expensive if land, labor, and
machinery are all purchased and charged to the
cost-return ledger. When interest rates on bor-
rowed money are high, a blueberry farm may take
many years to break even. During the 4 years that
pass before the first paying crop is harvested, ac-
cumulated interest costs may nearly equal the initial
establishment cost. If a grower already owns suitable
land and some of the necessary machinery, and if
he can provide some of the labor himself, the time
required for the farm to show an overall profit is
greatly reduced. The inputs required in establishing
and maintaining a blueberry farm are listed in Table
1. The total cost for the first year is about $3000
per acre plus land costs. Most of this goes for purch-
ase of plants, installation of an irrigation system,
mulch, peatmoss, and labor. Maintenance costs in
years 2 to 4 are about $500 to $1000 per acre per

Table 1. Inputs per acre required in establishing a blueberry

Year one
Land costs
Plant costs (604 plants per acre)
Irrigation installation costs
Plow land, once, 0.5 hours
(Tractor, plow, and driver)
Disk Harrow, twice, 0.3 hour each
(Tractor, disk, and driver)
Lay off rows, once, 0.5 hour
(Tractor and driver)

Open furrows, twice, 0.3 hour each
(Tractor and driver)
Apply peat moss, once, 2.0 hours
(Tractor, trailer, and driver)
Fertilize, 5 times
Set blueberry plants, 5.0 hours
(Tractor, trailer, and driver)
Mulch beds, 5.0 hours
(Tractor, trailer, and driver)
Irrigation electricity
Inputs per year, years 2 and 3
Fertilize, 5 times
Spray 5 times, 0.5 hour each
Tractor, sprayer, and driver)
(Herbicides & Fungicide as recommended)
Mowing, 10 times, 0.4 hour each
(Tractor, mower and driver)
Pruning and hoeing, 20 hours
Irrigation electricity
Interest on establishment and pre-harvest costs
Harvesting and Marketing
Picking labor
Labor benefits
Market preparation (including marketing and advertising)

Site Selection
Climate, soil, and market considerations are im-
portant in site selection. The rabbiteye blueberry
is deciduous and requires some cold weather each
winter to induce strong flowering and good fruit set
the following spring. North of Ocala, chilling is
usually sufficient for good yields. Between Ocala
and the northern edge of Lake Okeechobee, lack
of chilling makes the feasibility of large rabbiteye
blueberry plantations uncertain, and south of
Okeechobee City, large blueberry plantations should
not be made without extensive preliminary trials.
We expect that part of the region between Ocala
and Lake Okeechobee will become suitable for
large-scale blueberry culture as new cultivars are
developed and more information is accumulated on
how blueberries react to marginally insufficient chil-
ling. In the meantime, only small, experimental
plantations should be considered for this area.
A problem with growing blueberries on the cent-
ral Florida peninsula is that the colder valley loca-
tions, which would seem best suited for blueberry
production because they provide the most chilling
and are not used for citrus, are notorious frost
pockets. By sunrise following still nights, tempera-
tures may be 15F colder in frost pockets than on
surrounding hills. Blueberries are far less prone to
crop loss from spring frost than are peaches and

apples. Nonetheless, frost pockets should not be
used for blueberry plantations anywhere in the

One factor that favors central Florida as a
blueberry production area is season of ripening. In
the fresh fruit market, the earliest blueberries that
ripen in Florida will receive the best markets and
the highest prices. This will become increasingly
true in the future, as rabbiteye production expands
in Georgia and other southeastern states. Lower
yields on currently available cultivars for central
Florida may be offset by higher prices, but it will
probably be years before experience shows whether
central Florida will come out ahead or behind of
northern Florida in this trade-off. Meanwhile, re-
search is continuing on the breeding of cultivars to
overcome the low chilling problem. Carefully plan-
ned blueberry you-pick farms located near central
Florida population centers do seem to be feasible,
albeit somewhat risky ventures at present, a primary
risk being possible low yields following mild win-

usually flower in March and ripen in

Rabbiteye blueberries

Blueberries have specialized soil requirements,
and although Florida has vast acreages of soils suit-
able for blueberries, there are many Florida soils
on which blueberry cultivation should not be at-
tempted. In some areas, suitable and unsuitable
soils occur in close proximity and care must be used
in choosing a site.
Blueberries require acid, well-drained soils. Soil
pH should be in the range 4.0 to 5.2. If necessary,
ask your county agent how to take a proper soil
sample. Soil pH readings from a plot of land some-
times require interpretation in light of the past use
of the land. Woodlands that have never been farmed
or planted to improved pasture should not be used
for blueberries if the pH is above 5.5. On the other
hand, farm and pasture land which has been limed
in the past may have an artificially high pH which
can easily be lowered by addition of sulfur. A pasture
with a pH of 6.5 may be separated by a barbed-wire
fence from woodland with a pH of 4.0. In such a
case, the pH of the pasture can usually be made
suitable for blueberries if powdered sulfur is har-
rowed into the soil 6 months or more before the
blueberries are planted. Soils high in phosphorus
or calcium do not make good blueberry sites. Grow-
ers in Arkansas have found that blueberries grow
poorly on soils with more than 2000 lbs per acre of
available calcium.
Soil texture and moisture status are important
considerations in choosing a site for a blueberry
farm. Very coarse, drought sands, such as those
on which sand pines were native, should not be
used for blueberries. Coarse sands that are slightly
less drought, such as those inhabited by the
longleaf pine-turkey oak association, may be suitable
for blueberries, but the timing of irrigation and
fertilization are more critical on soils with such low
water and nutrient-holding capacities. The sandy-
clay soils found in- parts of the Florida panhandle
are excellent for blueberries if sufficiently acid, as
they frequently are.
With respect to wetter soils, Florida has large
areas of acid flatwoods, where surface soils are un-
derlain at various depths by a hardpan layer. These
soils can be excellent for blueberries if they are not
too wet and if Phytophthora-resistant blueberry
cultivars are planted. The best way to determine
whether flatwood soils are too wet for blueberries
is to examine them after a period of very wet
weather. If the water table stays higher than 2 feet
below the surface for longer than 24 hours after a
heavy rain, the land is too wet. Sometimes such
land can be made suitable for blueberries by digging

drainage ditches and planting the blueberries on
beds, the height of which is determined by the
wetness of the land.

Preparing Land to Plant Blueberries

After land has been located that is in the proper
climatic zone and has a suitable pH and water status,
it must be prepared for planting. What needs to be
done depends on the condition of the land. Forest
land must be cleared. It should be noted in land
clearing that blueberries grow poorly where piles
of wood have been burned in the previous 5 years
because ashes raise the soil pH. On flatwood soils
underlain by hardpan and on other poorly-drained
soils, provisions must be made for drainage. These
may include land leveling to eliminate low pockets
where water settles and construction of drainage
ditches. On soils that occasionally become too wet,
beds should be prepared at least 1 foot high. It is
critical that such beds be oriented to facilitate water
runoff. Blueberries should not be planted on beds
if drainage is no problem. Ditch digging, bed con-
struction, and other operations that mix soil horizons
may have an adverse effect on soil pH. Problems
should not be severe if the pH was originally suita-
ble, but high-pH spots caused by soil mixing should
be treated with sulfur before planting.
Any necessary adjustments to soil pH should be
made well before planting. Soil pH can be lowered
by discing in powdered sulfur. As discussed earlier
with respect to site selection, there are limitations
on how far downward the pH can practically be
adjusted. On soils that are naturally high in pH,
the pH tends to rise back to its original level as the
effects of the sulfur wear off. Blueberries should not
be planted on such soils. Sulfur can be used effec-
tively on soils that are naturally at 5.5 or lower and
on soils that were acid in their native condition but
have been limed.
The pH adjustment with sulfur should be done
at least 6 months before planting, because the chem-
ical reaction by which sulfur lowers the pH is slow.
If the pH is 5.2 or lower, no adjustment should be
made. Otherwise, the amount of sulfur to add is 1
pound per 100 square feet (500 pounds per acre)
for every pH point above 5.2. The entire field
should be treated without regard to where the rows
will be. The soils should be harrowed after the sulfur
has been broadcast to mix the sulfur with the top
4 inches of soil.
In addition to clearing the land and making any
necessary provision for drainage and pH reduction,

you should also begin a weed control program in
preparation for planting blueberries. Weed control
is very difficult in blueberries for the first 2 years
after planting, and everything possible should be
done before planting to reduce later problems.
Bahiagrass, bermudagrass, and othe aggressive pe-
rennial grasses should be eliminated by spraying
with glyphosphate in September before winter
planting. In old fields, weeds should be repeatedly
destroyed before maturity for one full year prior to
planting blueberries in order to reduce the popula-
tion of weed seeds.


Provision should be made for irrigating blueber-
ries in Florida. On moist soils with good water-hold-
ing capacity blueberries could be grown without
irrigation, but the risk of plant loss during establish-
ment years and crop reduction in subsequent years
makes this inadvisable. Drip irrigation, sprinkler
irrigation, and overhead irrigation are three types
that can be used. Drip systems have been the most
popular with Florida growers because of lower in-
stallation costs and more efficient placement of
water which reduces the amount of water that must
be added. A reason for minimizing the amount of
water applied, aside from pumping costs, is that
most Florida groundwater has a pH above 7.0 and
contains dissolved calcium carbonate which raises
the pH of the soil if added in large amounts. The
irrigation system should be installed before plant-
ing. Blueberries should be irrigated with discretion.
Rainfall, soil type, plant age, and season of the year
should be considered when deciding whether or
not to turn on the irrigation. In wet years, irrigation
may not be needed at all. Newly-set plants have
the most critical water needs: they are most sensitive
to overwatering and underwatering. Too much
water is as damaging as too little. In dry years,
irrigation is important on fruiting plants during the
fruit development period. Dry weather during this
period followed by heavy rains during ripening can
result in much fruit loss due to split berries. This
problem can be minimized by irrigation during dry
periods in the spring and early summer.

Planting the Blueberries
Rabbiteye blueberries should be planted in rows
12 feet apart with no more than 6 feet between
plants within rows. This requires 604 plants per
acre. Higher yields per acre could be obtained in

years 4, 5, and 6 by reducing within row plant space
to 3 feet, but this would double the cost of plants.
Eventually plants will sprout enough suckers to
form a continuous hedge down the row. Plant rows
should be thoroughly disced before planting. Rows
should be run so as to facilitate drainage if drainage
is a problem.
December is the best month for planting blueber-
ries in Florida. January and February are also ac-
ceptable, but give plants less time to establish roots
before spring growth begins. Vigorous two-year-old
plants are best for setting in the field. Small plants
are harder to protect from weeds, and older plants
suffer more transplanting shock. Two-year old plants
have been grown for one year in a field nursery
following propagation. If plants grown in pots are
set in the field, it is important to break up the root
ball with several vertical slashes of a knife. In trans-
planting blueberries, care should always be taken
to prevent the roots from drying out.
Several studies have shown that burying a gallon
of moist acid peat moss beneath each plant at the
time of planting will result in faster plant growth.
Sawdust and wood chips should not be used in this
way because they take nitrogen from the soil as they
decay. If the planting is made on good blueberry
soil, burying peat moss is not essential, and the cost
of the operation may exceed its benefits. If peat
moss is used, a 2-gallon hole should be dug for the
plant. One gallon of topsoil should be mixed with
1 gallon of moist peat moss and this mix should be
placed under and around the plant's roots as it is
planted. Another way of applying peat moss is to
spread it in the planting row and mix it with the
soil by use of a rototiller. The peat-soil mixture is
then placed around the blueberry roots when the
planting hole is refilled. Never put fertilizer in the
hole at the time of planting. Blueberries should be
pruned when transplanted to remove 50% of the
top. All flower buds should be removed in this


Mulching blueberries is expensive in Florida but
highly beneficial. Mulch helps control weeds and
helps to keep the soil moist and cool. Pine bark and
pine straw make the best mulches. Wood chips and
rotten sawdust are satisfactory but fresh sawdust
should be avoided. A good mulch is 4 to 6 inches
deep and covers a band 4 feet wide centered on
and running continuously down the plant row. An
alternative which requires less mulch is to mulch
only the area within a circle two feet around each

Weed Control

Weed control during the first two years is prob-
ably the most difficult problem in establishing a
blueberry plantation. Blueberries grow rather
slowly for the first year or two and their growth and
survival can be severely reduced by weed compet-
ition. Perennial grasses should be eliminated by
ploughing or with herbicides the summer and fall
before planting. The planting rows should be
thoroughly disced and weed-free at the time of
planting. Mulching is extremely helpful in weed
control. Most blueberry growers try to maintain a
weed-free strip at least 4 feet wide centered on the
plant row throughout the life of the plantation. The
middles between rows can be allowed to cover with
grasses which are maintained by mowing. Native

grasses or centipede are much superior to Bahia-
grass, which grows too fast and requires very fre-
quent mowing.
Herbicides can be useful in controlling weeds in
blueberries if used with great care. Paraquat,
glyphosphate, and pre-emergence herbicides can
all destroy blueberry plants if misused, and some
are highly toxic to man. Carefully read the safety
precautions on the label before using any herbicide.
If necessary, check with your county agent as to
safe use. When plants are small, herbicides are
usually applied with a backpack sprayer. When
plants become larger, herbicides can be applied to
the soil around the plants with a tractor-drawn
sprayer that is shielded to keep the spray from
touching the blueberry plants. For proper her-
bicides to use in young and older blueberry planta-
tions consult Table 2.

Table 2. Some herbicides used for weed control in blueberries.


Time of

Dichlobenil Casoron WP 8-12 Ibs. Early spring before
G 100-150 lbs. weed seed germina-
tion or after cultivation.

Dinoseb General OS,WE

Paraquat Paraquat CL

Simazine Princep G

Terbacil Sinbar WP

1-2 qts.

Anytime during
growing season.

1-2 qts. Apply before
emergence of new

50-100 Ibs.
2 V2-5 Ibs.
4.4 lbs.

Early spring or split
application in the
spring and fall.

2-4 Ibs. Apply either in the
spring or after harvest
in the fall before
weeds emerge or
during early seedling
stage of weed growth.

*WP-wettable powder, G-granule, OS,WE-oil soluble, water emulsifiable,
** Product per treated acre.

Weeds Controlled and Remarks

Annual broadleaf weeds and grasses. Follow
application immediately with shallow mechanical
incorporation. Do not use on light sandy soil. Do not
graze livestock in treated area. Do not apply within 1
month of harvest.

Controls broadleaf weeds and grasses. Use 10-20
gals diesel oil or weed oil. Up to 4 applications per yr.
Use only on plantings 2 yrs. or older. Do not treat 30
days before harvest. Apply before weeds reach 6 in.
tall. Avoid contacting crop foliage, blossoms, or fruit

Controls most annual grasses and broadleaf weeds.
Perennial weeds are desiccated. Use a non-ionic
spreader at 8 oz/100 gals. Apply as a coarse spray to
avoid drift injury from fine spray mist.

Controls certain annual grasses and broadleaf weeds.
Use V2 the rate recommended on plantings less than 6
months old. Do not apply when fruit is present. Rate
depends on soil texture.

Controls annual grasses and broadleaf weeds with
partial control of perennials at higher rates. Amount
of product used will vary according to soil texture and
organic matter. Do not use on sand or loamy sand with
less than 3% organic matter. Avoid contact of foliage
and fruit with spray or mist. Do not use on eroded areas
where subsoil or roots are exposed. Do not use on
unhealthy bushes.
CL-concentrated liquid, WDG-water dispersible granule.

Common Trade Formu-*
Name Name lation


The primary goal in fertilizing blueberries is to
promote rapid vegetative growth in young plants
(usually the first 3 growing seasons) and heavy fruit-
ing thereafter. A key to obtaining rapid early growth
is frequent application of fertilizers that contain
nitrogen in the ammonium form. Ammonium sulfate
is most often used. Ammonium nitrate and other
nitrate-containing fertilizers should be avoided be-
cause nitrate ions are very damaging to blueberries
on certain soil types. Fertilizers of any kind can
damage or kill blueberries when applied in excess.
Blueberries have a low tolerance for fertilizers, and
fertilization rates that are ideal for other crops may
kill blueberries. Because of variable interactions
between fertilizers and soil types, soil moisture
status, mulching practices, plant age and plant
growth status, it is hard to give simple rules for
fertilizing blueberries. Each grower needs to adjust
his fertilization rate based on the plant response he
observes on his farm. A generalized rule is that
plants during the first 4 or 5 growing seasons should
be given as much ammonium sulfate as possible
without causing fertilizer injury. Mild fertilizer in-
jury is indicated by brown-colored leaf spots, par-
ticularly around leaf margins and on younger leaves.
These appear 1 to 5 days after the fertilizer has been
dissolved by rain or irrigation. More severe fertilizer
burn causes leaf drop and possibly plant death.
Blueberries should not be fertilized when the leaves
are wet, because even small amounts of granular
fertilizer that sticks to the leaves and dissolves in
water can burn the leaves.
A new blueberry plantation should be fertilized
according to the schedule described below for the
first year. The schedule starts with a plantation set
out in December at 6 ft X 12 ft spacing. Do not
fertilize at the time of planting. On February 1, an
azalea-camellia fertilizer mix (approximately 5-10-10
with the nitrogen mainly in the ammonium form or
in the form of water insoluble N) should be broadcast
evenly over a circle of 2 ft diameter centered on
the plant, with 1 ounce used per plant (37 pounds
per 600 plants on an acre). Six weeks after this
fertilizer has been dissolved by 0.5 inch of rain or
more, plants should be fertilized with ammonium
sulfate, using 3/4 ounce per plant (28 pounds/acre)
in a circle of 2 ft diameter. Ammonium sulfate
should be added at 3/4 ounce per plant three more
times during the growing season, on approximately
the following dates: May 15, July 1, and September
1. If rainfall over 0.5 inch does not occur within 2
weeks after a fertilizer application, the subsequent
fertilization should be delayed until at least 6 weeks

after rain has dissolved the previously applied fer-
Fertilization the second year follows the same
pattern as for the first with two exceptions: (1)
because the plants are larger, the fertilizer should
now be braodcast evenly within a circle of 3 ft
diameter surrounding each plant; (2) the amount of
ammonium sulfate applied per plant per application
should be increased to 1 ounce. After the second
growing season, the best fertilization procedure will
depend on the growth of the plants. On relatively
fertile soils where plant growth is rapid and plants
are approaching the optimum size for production,
fertilization could be reduced by reducing the fre-
quency of ammonium sulfate applications.
Two other possible fertilization concerns with
blueberries are pH maintenance and micronutrient
provision. Soil pH should be maintained in the
range 4.0 to 5.2. Fertilizer practices, irrigation with
high pH-water, and other processes may cause
gradual changes in soil pH. If soil pH rises above
5.5, powdered sulfur should be broadcast at the rate
of 1 pound per 100 square fee (450 pounds per acre)
over the entire field. This should not be disced in
as was recommended for pre-planting sulfur appli-
cation, because discing would damage the blueberry
roots which lie just below the soil surface. Am-
monium sulfate applied as fertilizer will also help
to keep the soil pH low.
Iron deficiency is a common problem with
blueberries. The most visible symptom is interve-
nial leaf cholorsis, most conspicuous on new growth
flushes. Iron deficiency in Florida is almost always
caused by high soil pH or by excessive calcium or
phosphorous levels in the soil rather than by lack
of soil iron. High pH immobilizes iron within the
soil, making it unavailable to the plant. The best
cure for iron deficiency is to lower the soil pH. In
the short term the problem can be alleviated by
application of iron chelates (sequestered iron) either
to the soil or directly to the chlorotic leaves as a
water spray.


Blueberries should be pruned by removing 50%
of the top at the time they are transplanted to the
field, and all flower buds should be removed at the
same time. One year later, plants should be pruned
to remove all flowers before they begin to develop
into fruit. Fruit production during the first 2 years
in the field can slow the growth of the plant, and
should be prevented by pruning. Most blueberry
flowers are clustered at the tips of the branches,

and these flowered tips should be pruned off at or
before the time of flowering. Alternately, the flow-
ers could be picked off by hand.
Except for flower removal, no pruning is neces-
sary until the plants get too large for easy fruit
harvest. Detailed pruning will promote the highest
yields and greatest plant vigor but requires more
time than most growers consider practical. This
involves removal of dead or damaged wood, removal
of weak, twiggy growth, and selective removal of
older canes to promote bush renewal. Growers have
tested various other pruning systems that give ac-
ceptable results. These range from sawing the plant
back to a height of 1 foot with a chain saw every 5
years to removal of 1 year's growth with a hedger.
The best time to prune bearing plants is shortly
after the fruit has been picked. This gives the plant
time to grow new fruiting twigs that will produce
fruit the following year.

Diseases and Insects

The established highbush blueberry industries in
other parts of the country are afflicted by many
diseases and insects. Currently, blueberry disease
problems in Florida are being controlled primarily
through resistant cultivars, use of disease-free plants
for planting and by avoiding wet soils as planting
sites. Disease and insect problems can be expected

to increase as the Florida blueberry industry gets
older and larger. Insecticides should never be used
on blueberries or any other crop until they are
absolutely essential to prevent serious damage.
Overuse of insecticides kills insect predators, many
of which are other insects, and sets into motion a
vicious cycle in which more and more sprays are
necessary to control insects that were previously
controlled by natural predators. If insects appear to
be a problem, consult a county agent before spray-


Birds can be a problem in blueberries. This is
particularly true with small plantings in urban areas.
Bird damage can be prevented by covering indi-
vidual plants or entire plantings with nylon or plastic
nets. Various noise-making devices have been
tested with only limited effectiveness. A chemical
bird repellent (Mesurol), which deters but appa-
rently does not injure birds, has been tested by
some growers and has been cleared for use in Michi-

Rabbiteye Cultivars

The blueberry cultivars discussed in this section
all produce high-quality berries that are essentially
indistinguishable in the marketplace. Although av-

rI;- > If left unpruned, a rabbiteye blue-
berry bush will eventually reach a
r.. height of 4 to 7 meters.

: !

ailable cultivars differ somewhat in such berny
characteristics as flavor, size, color, and seedines:;,
these characteristics- are not as important in the
choice of cultivars for Florida as ripening time,
suitability for mechanical harvesting, yield poten-
tial, ability to set crops after mild winters, and
compatibility in cross-pollination. Which cultivars
are best to plant will depend on plantation size and
location and on harvest method and marketing
Rabbiteye blueberries require cross-pollination
between different cultivars for acceptable yields. A
minimum of two different culitvars that bloom to-
gether must be interplanted, and there are reasons
for expecting even higher yields when three or more
compatible cultivars are interplanted. Cultivars
should be planted in alternating rows so that each
row is bordered by a row containing a different
cultivar. New cultivars are continually being de-
veloped and tested in Florida, and growers should
check with the county agent for the latest recom-

Fruit of improved rabbiteye cultivars are large, light blue in
color, and have a longer shelf life than most other kinds of

Table 3 gives 1983 cultivar recommendations
grouped according to area of adaptation and market-
ing strategy. For early shipping, Aliceblue, Bec-
keyblue and Climax should be interplanted for good
cross-pollination. For you-pick, Woodard,
Bluebelle and Delite should be added. To get the
best cross-pollination among these six cultivars, the
three early cultivars (Aliceblue, Beckyblue, Climax)
should be planted in three-row groupings (ABC,
ABC, ABC, etc.) on one side of the field and

Woodard, Bluebelle, and Delite should be planted
in three-row groupings (WBD,WBD, WBD) on the
other side. In the panhandle and north of Lake City,
where Tifblue is recommended, it should be added
to the Woodard-Bluebelle-Delite group.

Table 3. List of Recommended Blueberry Cultivars for

Cultivar name
Use categories:

Use Category
1 2 3 4 5

(1) You-pick farm Ocala northward
(2) Early shipping (May 25-June 15) Ocala
(3) Late shipping (June 15-July 5) Ocala
(4) For test, you-pick, Orlando to Ocala
(5) New. Not thoroughly tested in Florida.
Try one test row from Ocala northward.
(6) Highbush. Plant on well-drained soils.
* Tifblue should be planted only in the
panhandle and north of Lake City

Fruit from Aliceblue, Beckyblue, and Climax can
be picked from June 1 to June 15 at Gainesville in
an average year. This fruit would be the earliest
rabbiteye blueberries on the market. It ripens with
the last half of the North Carolina highbush crop,
but the volume of blueberries available at that sea-
son is still low and fresh markets should be good.
Woodard was excluded from the list of shipping
berries in Table 3 because its fruit is less firm than
is desirable for shipping. It is, however, a reliable
producer and is highly recommended for you-pick
farms. The ripening season for Woodard averages
about one week after Aliceblue, Beckyblue, and
Climax. For any one cultivar, the harvest period
typically extends over about 3 weeks. By using early
and late cultivars, a grower could extend his harvest
season to a period of about 6 weeks if this were


Blueberry yield reports vary widely, depending
on farm location, plant age, cultivars, level of man-
agement, and whether or not one averages the


poorer years in with the better. Pruning and flower
removal prevent fruiting for the first 2 years after
planting. A crop can be expected the third year,
and by the fifth year, the plantation should be
nearing full production. Good growers in north
Florida report long-term average yields of about 3
tons per acre per year. If rejuvenated by periodic
pruning, plantations can be expected to maintain
these yields for 30 years or more.

Southern Highbush Cultivars
The northern highbush has long been the most
important cultivated blueberry in the U.S. The
large Michigan and New Jersey industries are based
entirely on highbush cultivars, and 90% of North
Carolina's production is from highbush. The high-
bush cultivars used in these areas are early ripening
and produce high-quality fruit. Unfortunately, they
cannot be grown profitably in Florida because of
their high chilling requirement and disease suscep-
Efforts were begun more than 30 years ago to
develop varieties of highbush that could be culti-
vated in the humid southeast, and these efforts are
continuing. Three cultivars have been released for
Florida: Sharpblue and Flordablue mature their
crops between April 25 and May 15 in an average
year in Gainesville, and these are the earliest
blueberries available in the U.S. Avonblue ripens
at Gainesville from May 10 to May 20. Sharpblue
berries are not firm enough to ship well, but Flor-
dablue and Avonblue berries are firmer.
Experimental plantings of these cultivars in
Florida have shown that they yield well and that
fruit has high quality. They have also shown two
major problems: birds and root rots. Birds have
been more serious a problem with highbush than
with rabbiteyes for at least two reasons: (a) Birds
have less other food to eat at the earlier, highbush
ripening season, and some migratory species,
among them the cedar waxwing, are abundant in
Florida during highbush season but have left the
area by rabbiteye season, (b) Most experimental
highbush plantings have been small. Birds do prop-
ortionally more damage in small plantings than in
,larger ones.
In some locations in Florida, the southern high-
bush cultivars have failed because of root rots. High-
bush are much more susceptible to this problem
than rabbiteyes. Root rots are more severe on heavy
or poorly-drained soil than on lighter, well-drained
Production of highbush blueberries in Florida
will probably someday become an important indus-

try because of the great advantages of early ripening.
At present, however, highbush plantations in
Florida are still experimental. Growers who pro-
duce highbush blueberries in Florida must be able
to obtain a higher price for their fruit than is received
for rabbiteyes, because of higher production costs.
Growers attempting highbush production should
choose well-drained soils, mulch heavily, and be on
the lookout for birds and root r6ts. Bird-repellant
chemicals that do not injure the birds and systemic
fungicides are being tested and may facilitate high-
bush production in the future.

Blueberries are propagated by hardwood or
softwood cuttings. Experienced propagators in
Florida can sometimes produce plants large enough
to set in the field in one year from hardwood cut-
tings, but 2 years is a more reasonable expectation.
A 50-50 volume mixture of Canadian peat moss with
Perlite or of finely-ground pine bark with Perlite is
ideal for rooting blueberries. Ground beds or raised

Rabbiteye blueberry seedlings are used to develop new culti-
vars. Plants for production fields are propagated by softwood
or hardwood cuttings under mist.

benches may be used. To build a ground bed, first
construct a cold frame with sides 12 inches high.
Place 4 to 6 inches of gravel or pine bark on the
bottom to improve drainage. Cover this with 8
inches of rooting mix. An intermittent mist system
should be provided for softwood cuttings.
Hardwood cuttings can be rooted under mist or
under 50% shadecloth with frequent brief periods
of overhead irrigation.
Hardwood cuttings are taken in January and early
February when stock plants are dormant. Cuttings
should be about 6 inches long. They should be taken
from strong wood from the previous growing season
that has no flower buds. Such wood can be obtained
from large stock plants that were pruned severely
the preceding spring. Hardwood cuttings should be
stuck 4 inches deep in the rooting medium, leaving
only an inch or two above the medium. Both
hardwood and softwood cuttings should be spaced
1 1/2 inches apart in rooting beds. The most critical
period during the rooting of hardwood cuttings is
the 2 months after the cuttings begin to leaf out.
Leafing occurs at least a month before roots form,
and even temporary wilting of the leaves during
this period can greatly reduce the rooting percen-
tage. Intermittent mist, or shadecloth combined
with frequent light irrigation (once each hour of
daylight for 2 minutes each time) can prevent wilt-
Softwood cuttings are taken after the first flush
of new growth becomes semi-hard in May. Good
cutting wood can be obtained in large quantities
from strong stock plants from which all the flowering
branches were removed in early March. Cuttings
should be about 4 inches long. No leaves should be
removed except from the bottom 1 inch of the
cutting. Cuttings should be stuck 1 inch deep in
the rooting medium. Intermittent mist should be
provided. Leaves should never be allowed to dry
at any time. A major cause of loss with softwood
cuttings is power outages or pump failures that
interrupt the delivery of mist during hot, sunny
weather. Cuttings frequently defoliate after such an
incident, and rooting rate may be severely reduced.
Most mist systems are equipped with two time-
clocks. One turns the whole system on at sunrise
and off at sunset. Mist at night is unnecessary and
promotes the growth of damaging fungi. The second
timeclock activates a 5-second burst of mist approx-
imately once every 5 minutes. One way to reduce
the risk of cutting loss during power outages is to
install a mist system that mists continuously during
power outages.
Hardwood cuttings stuck in ground beds in Feb-
ruary will generally have roots by May 15. They

should then be fertilized once every 2 weeks until
October 1. One good fertilization schedule is to
alternate ammonium sulfate with water-soluble 20-
20-20. These should be dissolved in water and
applied as uniformly as possible with a sprinkling
can. For 20-20-20, dissolve 1/2 pound water-soluble
20-20-20 in 16 gallons of water. Sprinkle 1 gallon
per 25 square feet over the plant bed and wash the
leaves immediately with irrigation water.
Softwood cuttings stuck on May 15 will be rooted
by July 15. They should then be fertilized every 2
weeks as described for rooted hardwood cuttings.
Rooted softwood cuttings should be grown for an
additional year before being planted in a production
field. One way to do this is to move them during
December from the rooting bed to a high-density
nursery equipped with overhead irrigation. Plants
should be set 6 inches apart in rows 1 foot apart.
Starting on February 15, plants should be fertilized
every 6 weeks by broadcasting ammonium sulfate
at the rate of 1/2 pound per 100 square feet over
the tops of the plants when the leaves are dry. If
the soil is good and weeds are controlled, very nice
plants with excellent root systems can be obtained
by the following December.

For More Information
Check first with your county agent if you have
questions or problems with blueberries. He may
have the needed information or know where to get
it. The Florida Blueberry Growers' Association is a
grower organization which has as one of its goals
the dissemination of information on blueberry pro-
duction in Florida. The Association normally spon-
sors half-day blueberry growing workshops each
spring and fall. Your county agent can put you in
touch with association officers. Large libraries fre-
quently have books and circulars on blueberry pro-
duction. Most of this information pertains to north-
ern highbush blueberries, but some is relevant to
rabbiteyes. A particularly thorough book is
Blueberry Culture, edited by Paul Eck and Norman
F. Childers, Rutgers University Press, 1966, 378

Blueberries appear to be one of the most promis-
ing fruit crops that can be grown in northern Florida.
Markets are excellent in early June when early
rabbiteye cultivars mature in Florida. Blueberries
are an excellent crop for pick-your-own markets.
Blueberry growing is a very specialized kind of
farming, and prospective growers need to learn all
they can about blueberries before planting.


We thank Al Snapp, Hainesworth Farm, Alachua,
Florida and Pat Hartmann, Hartmann Blueberry
Plantation, Earlton, Florida for many helpful
suggestions during the preparation of this hand-

This publication was promulgated at a cost of $1,113.00 or 29 cents per copy, to inform extension agents,
growers and homeowners about production of blueberries in Florida. 5-2M-84.

SCIENCES, K. R. Tefertlller, director, In cooperation with the United States Department of Agriculture, publishes this Infor-
mation to further the purpose of the May 8 and June 30, 1914 Acts of Congress;and Is authorized to provide research, educa-
tional Information and other services only to Individuals and Institutions that function without regard to race, color, sex or
national origin. Single copies of Extension publications (excluding 4-H and Youth publications) are available free to Florida
residents from County Extension Offices. Information on bulk rates or copies for out-of-state purchasers Is available from
C. M. Hinton, Publications Distribution Center, IFAS Building 664, University of Florida, Gainesvllle, Florida 32611. Before publicizing this
publication, editors should contact this address to determine availability.


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