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Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 550
Title: Production of vegetable plants in seedbeds on sandy soil
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027085/00001
 Material Information
Title: Production of vegetable plants in seedbeds on sandy soil
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 24 p. : ill. ; 23 cm.
Language: English
Creator: Burgis, D. S.(Donald Stafford), 1913-
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1954
 Subjects
Subject: Vegetables -- Planting -- Florida   ( lcsh )
Vegetables -- Soils -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by Donald S. Burgis.
General Note: Cover title.
General Note: "A contribution from the Gulf Coast Experiment Station"--T.p.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027085
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000926397
oclc - 18277032
notis - AEN7069

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Full Text


Bulletin 550


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLARD M. FIFIELD, Director
GAINESVILLE, FLORIDA
(A contribution from the Gulf Coast Experiment Station)








Production of Vegetable Plants in

Seedbeds on Sandy Soil


By DONALD S. BURGIS


S*0 A
4


October 1954





























CONTENTS


PAGE


CHOOSING THE LOCATION ...............


SOIL SELECTION...


PREPARING THE SEEDBED ..


THE SEEDBED COVER ...


FERTILIZING THE SEEDBED


HERBICIDES, NEMATOCIDES AND SOIL FUNGICIDES


SOWING THE SEEDS ..... .....


WATERING THE SEEDBED


INSECTICIDES


......--....-.-...- ... 3


.-..... -..- ...-.-.- .. 6


9
........ -- 9
... .... .-. ...-.- .- 9


..-..-......- .-.. 14


-.....- 21


FUNGICIDES

SUMMARY


- ------....... ........ 23









Production of Vegetable Plants in

Seedheds on Sandy Soil

By DONALD S. BURGIS

Florida's highly specialized vegetable growing industry de-
mands that millions of high quality vegetable plants be produced
for field setting each season. The planning, preparation and
care of the seedbeds necessary for the production of these seed-
lings are of major importance. The success of the farming
operation usually is dependent on the success or failure of the
seedbed. It is common grower practice to plant twice as much
seedbed space as is actually needed in order to compensate for
losses due to poor growth, adverse weather conditions, rootknot
infestation, damping-off and insect damage. However, recom-
mendations can now be made concerning types of cover, irriga-
tion practices, fertilization, chemical weed killers, rootknot
control measures, soil fungicides and soil insecticides that should
greatly reduce the hazards involved in seedbed management.
With careful planning one can reduce the seedbed area so that
the reserve area planted is not over 10 percent more than ac-
tually needed.
Two types of seedbeds employed by vegetable growers are:
(1) seedbeds of a temporary nature which are located in an area
for one crop season and abandoned, and (2) permanent-type
beds which are maintained in place year after year. All aspects
of seedbed management practice discussed herein can be applied
to either production method. A third way of growing plants.
"field seeding" in the row where the crop is to be grown, is not
within the scope of this work except as regards the use of foliar
fungicides and insecticides during the early part of the growing
period.' This is discussed under Fungicides and Insecticides.

CHOOSING THE LOCATION
The seedbed area should be chosen only after a number of
factors have been considered.
The seedbed site should be one which is known to be well
drained at all times. One which is "normally safe" is not good

For management of two- to three-drill row cabbage seedbeds see Fla.
Agr. Expt. Sta. Press Bul. 656.






Florida Agricultural Experiment Stations


enough. Summer rainfalls of 6 to 12 inches in 24 hours are
common enough to make a positively safe area a must (Fig. 1).
Spring seedbeds are often subjected to two- and three-inch rains
when masses of cold air move in from the northwest. Saturated
soil conditions at such times will damage seed germination, re-
tard plant growth, and further the development of cool weather
types of damping-off fungi. Control of the general drainage of
the seedbed area is also important. Arrangements should be
made in advance so that drainage ditches may be dammed to
prevent excessive run-off in a very dry season. A low water
table encourages the buildup of rootknot nematodes which
multiply rapidly under such conditions. It also brings about
excessive leaching of fertilizer salts by the large amounts of
water which must be applied to compensate for the rapid drying
out of the soil.
If the land sloping away from the seedbed site is cleared so
that there is nothing to obstruct the drainage of cold air, the
beds will be safe from all but the heavier frosts. Protection
from cold winds is as important as frost protection for winter
seedbeds. The cold drying winds of the Florida winter season
usually come from the west, northwest or north. Wind damage
can be minimized by choosing, if possible, a sloping area which
is bordered on the north and west by forested or uncleared

Fig. 1.-Seedbeds in a "normally safe" location flooded by rain during the
fall hurricane season.
















40


!rl .






Vegetable Plants in Seedbeds on Sandy Soil


land. Barriers of high vegetation will tend to force the wind
upward away from the seedbeds.
A simple way to test the seedbed site for the presence of
nematodes is to plant yellow crookneck squash or cucumbers.
The seed of either of these germinates quickly, producing a
rapidly growing plant which has a large root system. As soon
as the young plants have five or six true leaves they may be
dug and the roots examined for the presence of ectoparasitic
(surface feeding) and rootknot nematodes. The presence of
"sting" and "stubby-root" nematodes can be determined by
the general appearance of the roots. The "sting" nematode
feeds on the small feeder roots and kills them. Thus the root
system consists mainly of primary roots which have a brown
fibrous appearance. "Stubby-root" nematode attacks and kills
the growing tip of the primary roots. After the root tip is
killed many secondary roots are formed just above the killed
area-the tips of these in turn are killed. "Stubby-root" nema-
tode attack results in the production of short primary roots
terminated by bunches of very short brown secondary roots.
If rootknot galls are all that are found on the test plants (see
Fig. 2), other biologic strains of nematodes which attack the
roots of vegetables are probably present.









r ,



.- ^ r -


Fig. 2.-Rootknot galls on roots of young cucumber plants.






Florida Agricultural Experiment Stations


SOIL SELECTION
In south and central Florida the soils of the higher elevations
are usually of a sandy nature. This physical characteristic in
itself accounts for the fact that most seedbeds are confined to
these areas. However, there are several other characteristics
of sandy soils which make them more desirable for seedbed pro-
duction than the heavier clay or muck types. The formation
of a crust by surface drying obstructs the emergence of germi-
nating seedlings and often causes severe losses. Sands do not
form a crust upon drying as do clay type soils. Seed germina-
tion and plant growth are more rapid in winter sowings on
sandy soil because the temperature of sandy soil is higher than
that of the heavier types due to better drainage.
The plant grower in Florida is faced with the difficult task of
"hardening" plants for field setting under conditions which will
not allow him to withhold water or expose the plants to cold
as can be done in more northern localities. The grower has
only one method of "hardening" to which he can resort-that
of withholding fertilizer, and only with soil of low fertility is
this possible. Thus, the seedbed is heavily fertilized at the
onset but no fertilizer is added as the plants approach the re-
quired size for field setting.

PREPARING THE SEEDBED
The first thing to consider in preparing the seedbed site is soil
reaction. The pH best suited for growing vegetable seedlings
lies in the 5.5 to 6.0 range. The pH 5.5 figure should be taken
as an absolute minimum, since the acidity of the soil will often
increase somewhat during the cropping season. If, in attempt-
ing to amend the soil reaction by the addition of calcareous
materials, one should err to the extent that the pH increases
to 7.0, he has no reason to worry. A very high pH will limit
the availability of iron, manganese, zinc and possibly copper,
but these materials can be supplied as foliar sprays. However,
a low pH not only suppresses the activity of the soil nitrifying
and nitrogen-fixing micro-organisms but the acidity of the
soil solution limits root formation and consequently the up-
take of all the major nutritional elements necessary for plant
growth. Any amendment should be added far enough in ad-
vance for the pH to become stable by the time the seedbeds
are to be made up. The time necessary for this will depend
upon existing moisture conditions, organic content of the soil







Vegetable Plants in Seedbeds on Samdy Soil


and the particular material used. Because it will exert its
full effect in four to six months, dolomitic limestone which is
commonly used for this purpose (see Table 1) should be applied
before the summer rains.

TABLE 1.-APPROXIMATE QUANTITIES OF LIME TO BE BROADCAST PER ACRE
ON LIGHT SOIL TO CHANGE THE SOIL REACTION TO PH 5.5 FROM LOWER
PH VALUES. ADAPTED FROM FLA. AGR. EXP. STA. PRESS BUL. 513.

pH of Test Pounds Hydrated Lime Pounds Ground Limestone:
Soil Sample per Acre per Acre

3.6 3,500 4,725
3.8 2,700 3,650
4.0 2,150 2,900
4.2 1,700 2,300
4.4 1,200 1,625
4.6 750 1,025
4.8 500 675
5.0 300 400
5.2 200 275
5.4 100 150

*Either calcium limestone or dolomitic limestone. The latter contains magnesium
which would be beneficial 'co soils lacking that element. The rapidlity with which ground
limestones react in changing soil acidiy depends upon the degree of fineness of the
pariicies. The fine partic.es react more quickly than the coarser particles. The presence
of both in the ground limestone is desirable.

The seedbed site should be plowed and disked, several times
if necessary, to break up all coarse pieces of organic material
in the soil. The number of damping-off fungi and nematodes
in the soil can be reduced by clean cultivating and disking
the area from time to time before making the bed. Allow the
soil surface to dry out between diskings.
In laying out the seedbed run the bed generally north and
south. This allows shade from the rolled-up cover to be evenly
distributed over the bed. If the beds run east and west, parallel
to the sun's path, the same part of the bed will be shaded by the
cover all during the day and plants in this area will become
spindly and be of little value for field setting.
The usual width of a seedbed is four feet. This is the maxi-
mum width which allows a man to work the whole bed from
one side. The 70-inch wide muslin cloth which is standard for
use as a cover will fit conveniently over a 5 foot "A" frame
(Fig. 3), allowing enough pitch to shed a major portion of the
hardest rain. However, seedbeds up to 8 feet wide may be
found. As a rule the wider beds are not covered but are mulched
with straw or sawdust to provide protection against erosion
and driving rains.






Florida Agricultural Experiment Stations


THE SEEDBED COVER
As the real purpose of the seedbed cover is to shed water,
the grower who buys inferior grades of cloth is buying reduced
efficiency. The seedbed cover also serves as a barrier to cold
wind and will protect seedlings from light frosts. Double covers
of heavy muslin are used sometimes when celery beds are started
in July; however, one of these covers is removed as soon as the
young seedlings are well rooted.
Many growers have the false notion that the shading effect
of the cover is beneficial. The shading of growing vegetable
plants is seldom desirable. Shading: (1) makes plants so suc-
culent that they do not survive well when set in the field; (2)
increases the incidence of most diseases; and (3) encourages
long, weak (leggy) stem growth so that the plants are difficult
for a plant dropper to handle and totally unfit for machine plant-
ing. After germination is complete the covers should be kept
raised as long as possible each day. The alert operator can
lower his covers when a rain threatens.
Mildew which attacks cloth under wet conditions can be
controlled by spraying muslin cloth covers with a neutral copper

Fig. 3.-Five-foot A frame with a two-foot-high ridge covers a four-
foot-wide bed and allows sufficient room for the 70-inch-wide cloth cover.
The side boards shown here are optional.






Vegetable Plants in Seedbeds on Sandy Soil


fungicide. A good wetting of the cloth once a season with a
mixture of field spray strength as soon as the cover is spread
is sufficient.
FERTILIZING THE SEEDBED
The grower should use a 4-7-5 analysis fertilizer at the rate
of 3,000 pounds per acre of seedbed. This is applied broadcast
and worked into the upper inch of the soil surface a week or
10 days before sowing. Beds fertilized in this manner should
be maintained in a moist condition. If further information is
desired the grower should consult Fla. Agr. Exp. Sta. Bul. 514.
Fertilizer recommendations for cabbage, broccoli and cauliflower
seedbeds may be found in Fla. Agr. Exp. Sta. Press Bul. 656.
HERBICIDES, NEMATOCIDES AND SOIL FUNGICIDES
Seedbeds may now be treated before planting with chemicals
that control the three worst hazards of production: weeds,
nematodes and damping-off fungi. There are chemical com-
pounds which will control each of these pests or any combina-
tion of them. The ideal chemical should be: (1) non-toxic to
humans; (2) non-corrosive; (3) easy and simple to apply; and
(4) not persistent in the soil for longer than seven days. Each
Fig. 4.-Growth of nutgrass bordering area which had been treated with
methyl bromide gas three months before.


w~ss~ssaui






Florida Agricultural Experiment Stations


material recommended here has one or more of these desirable
qualities, but none has them all.
MC-2, liquid methyl bromide gas to which 2 percent chlor-
picrin teargass) has been added as a warning agent, is the best
pre-planting treatment for seedbeds where control of weeds,
nematodes and damping-off fungi is required. MC-2 is the only
soil treatment recommended here which will control nutgrass
(Fig 4). When treating a seedbed with methyl bromide it is
wise to include a one-foot margin extending beyond the bed
so the planting is not reinfested by the splash of rain or water
drip from the edge of the cover. After the bed is marked out,
a shallow ditch about three inches deep should be dug around
the bed so that the edges of the cover will drop into it. The
soil removed can then be replaced and tamped down to form
a seal (Fig. 5). Any length or width of bed can be treated at
one time but care should be taken to have the applicator tubes
not more than 20 feet apart. Some sort of support for the
cover should be laid along the center of the bed. Tin cans.
blocks of wood, pieces of irrigation tile, or any material which
does not have sharp edges will serve. Three types of cover
can be used: (1) a heavy canvas tarpaulin for covering soil
to be treated in pits; (2) sisal craft paper; or (3) polyethylene

Fig. 5.-Seedbed ready for installation of plastic cover. Edge of cover
will fit into trench. Note that applicator tube is inserted underneath ditch
and leads into large-mouth bottle which will hold any liquid gas until it
vaporizes.


***^''d






Vegetable Plants in Seedbeds on Sandy Soil


plastic sheeting for seedbed areas (Fig. 6). The plastic sheeting
is recommended because: (1) it is cheaper and more durable
than paper, and (2) it comes in wide (16 ft.) pieces that can
be cut to size.
MC-2 is applied at the rate of 2 pounds per 100 square feet
of bed area on sandy soil and 3 to 4 pounds per 100 square feet
on clay or muck soils. The gas-tight cover should be left over
the bed for 24 hours. Since methyl bromide is a liquid at 40 F.,
treatment should not be attempted unless the temperature is
500 F. or higher. If normal conditions exist after the cover
is removed, the bed may be aerated and planted within three
days. However, if wet conditions prevail this waiting period
should be increased to seven days and the bed aerated twice
during this period if possible. MC-2 is very toxic and every
care should be taken to avoid exposure to it.
Allyl alcohol is an excellent herbicide, giving control of all
broad-leaved weeds and grasses except nutgrass. It is equal
to methyl bromide as a soil fungicide, but it does not control
nematodes. For seedbeds in which the control of rootknot
is not considered important, allyl alcohol is recommended. As
a pre-planting treatment it is easy to apply and seed may be
sown within three days after application regardless of weather

Fig. 6.-Polyethylene plastic cover installed. The soil around the edge
should be pressed down with the foot as shown.


4,41






Florida Agricultural Experiment Stations


conditions. The alcohol should be diluted 1:200. Apply Y'gal-
lons of this mixture with a sprinkling can to each 100 square
feet of bed area. It is important that the treated surface be
moist at time of treating. Watering immediately after treat-
ment will increase effectiveness. Allyl alcohol is a deadly poison.
Excessive inhalation of the fumes could be fatal. Therefore,
it should never be used in an enclosed area. The concentrated
material is very caustic to the skin and should be washed off
immediately. A person handling this compound should wear
a mask, rubber gloves, boots and a rubber apron if possible.
Fumes from the diluted alcohol will be irritating to the nose
and eyes and long continued exposure, even in the open, should
be avoided.
When MC-2 or allyl alcohol is used as a pre-planting treat-
ment the soil is rendered sterile insofar as pathogenic organisms
are concerned. Some unnecessary stirring of the treated plot
can be avoided if the fertilizer is applied prior to treating. Since
treating kills the soil nitrifiers, the fertilizer used on treated
areas should supply at least one-half of the total nitrogen as
nitrate. If sterile soil is reinfested with disease organisms
these will multiply much more rapidly than under normal condi-
tions. Damping-off as a result of reinfestation in MC-2 and allyl
alcohol-treated plots can cause major losses. Strict sanitation
must be practiced. Animals such as dogs or chickens can reinfest
treated soil from the particles of soil carried on their feet. Culti-
vating tools should be cleaned thoroughly and dried before use.
A tool used in a treated area should not be laid aside in an un-
treated area and then put back until it has first been thoroughly
cleaned and dried.
If the control of nematodes is the prime factor to be con-
sidered in the management of the seedbed, then either DD or
EDB should be used. Overall treatment of the entire area
before the beds are made up has not proven satisfactory. As
the depth of penetration of DD or EDB is usually not more
than 10 inches, untreated soil from below the effective depth
is brought to the surface when beds are made up following an
overall treating. Treated surface soil is thus reinfested with
nematodes. For best results the beds should be made up and
then treated. Then the soil need not be stirred to a depth
exceeding three or four inches during the process of fertilizing,
seeding or subsequent cultivation. Either DD or EDB is applied






'egetable Plants in Secdbcds on. Saindy Soil


at the same rates as recommended by the manufacturer for
field use. The beds should be watered immediately following the
application. This water seal is important and greatly increases
the effectiveness of the treatment. Neither of these materials is
very toxic to humans. EDB is less corrosive to equipment than
DD. However, the chemicals are equally effective for the con-
trol of nematodes.
A mixture of allyl alcohol and EDB has proven effective for
the treatment of seedbeds. Four pints of a 1:4 stock solution
of 85 percent emulsifiable EDB is added to 50 gallons of 1:200
allyl alcohol-water mixture. Fifty gallons should drench 'LOt
square feet of bed. This mixture has given good nematode con-
trol and the fungicidal effect is often better than when allyl
alcohol is applied alone. When handling the mixture observe
the same precautions listed for allyl alcohol.
If no MC-2 or allyl alcohol treatment is made, control meas-
ures for damping-off organisms should be undertaken as soon
as the seeds have been planted. A copper drench applied to the
surface of the bed at this time will control pre-emergence damp-
ing-off of the germinating seedlings and, in most cases, exert
a residual effect sufficient to prevent an outbreak of the disease
during the seedbed growing period. Careful daily inspection
after the plants are up should enable one to detect any local
damping-off infections. These can easily be spot-treated so that
the fungus is killed.
The application of ONE copper drench immediately after
seeding should give a "preventive" effect which will last a
long time unless weather conditions are very unfavorable. Cop-
per drenches should never be added to the seedbed in repeated
doses with the assumption that a "curative" effect can be
obtained. Remember that a few crops such as cabbage, broc-
coli and cauliflower are more sensitive to copper than other
crops; the application of one drench will only injure them
slightly, while several drenchings would actually kill the seed-
lings.
Any of the many blue copper fungicides (not copper sulfate)
available should be satisfactory for making the seedbed drench.
Copper-A compound may be used at the rate of 6 pounds to
50 gallons of water. It has a metallic copper content of ap-
proximately 46 percent. If tri-basic copper is used the rate
should be 5 pounds in 50 gallons of water because its metallic
copper content is approximately 54 percent. Blue coppers





Florida Agricultural Experiment Stations


having lower metallic percentages should be used at higher
rates. Since copper is a very heavy material, the drench mix-
ture should be stirred continuously while it is being applied.
The overall drench may be applied with sprinkling cans or
with a power sprayer at the rate of 6 gallons of the mixture
per 100 square feet of bed surface. It is usually easier and
more economical to apply spot treatments with a sprinkling
can. Copper sprays are commonly applied to sandland celery
seedbeds for the control of damping-off organisms. Weekly
applications of 12:100 sprays have given good control with no
apparent phytotoxicity. Recent investigations have shown that
copper applied to the soil surface season after season builds
up a residue of copper which in time becomes toxic to seedlings.
For this reason seedbed areas should be shifted every few years
where this practice is used.

SOWING THE SEEDS
Careful attention should be given to sowing seeds. Celery,
endive, escarole, lettuce and romaine seeds, together with other

Fig. 7.-Tomato seedlings infected with late blight. Note that the plants
are too thick and the rows too close together, making effective spraying
impossible. This bed had to be destroyed.

IVM Ps'.iii-a AW






Vegetable Plant.s in Seedbeds on Salnd Soil


light seeds, should be broadcast and then barely covered with
soil. Row seeding is not necessary nxith these crops, as they
are seldom subject to foliage diseases which require the applica-
tion of fungicides. Seedlings of this type should be kept moist
until the plants have become well rooted. During warm, dry
weather it is desirable to cover the surface of seedbeds of this
type with wet burlap for a few days. However, care should
be taken to remove the covering as soon as the seeds have
germinated. Heavy seeds such as broccoli, cabbage, eggplant,
pepper and tomatoes should be sown in rows and covered not
more than one-half inch deep. To avoid the production of
leggy plants and to encourage large stem size, it is best to thin
the seedlings so that each plant is separated from the next
by approximately one-half inch. Do not make the rows too close
together (Fig. 7). It is important that the rows be five to six
inches apart because foliage diseases are very difficult to con-
trol unless a spray nozzle can be introduced between the rows
of plants. It is necessary to coat the stems and the undersides
of the leaves with a fungicide.

WATERING THE SEEDBED
Regardless of the method of watering employed, the person
charged with the operation must have a real understanding
of seedbed management. He must be familiar with his soil
type in order to judge whether it is too wet or too dry. Ex-
cessvie soil moisture following seeding will reduce seed germi-
nation by excluding oxygen from the soil and encourage the
development of damping-off fungi. If the soil becomes too dry
at this time the germinating seeds will be dried-out and killed.
As the seedlings become older the water level, with seep irriga-
tion, should be progressively lowered, or with overhead watering
the intervals between waterings should be lengthened. This
lowering of the water table develops seedlings with deeper and
more extensive root systems and at the same time discourages
the development of soil fungi.
The incidence of damping-off can be reduced by having the
bed surface dry by dusk, but since plants make a major portion
of their growth during the night, there should be sufficient
moisture in the soil below the dry surface to allow for this
growth acceleration. To have the proper moisture balance at
the beginning of the night period one must experiment to de-
termine just how late in the day water should be applied. If






Florida Agricultural Experiment Stations


the seedling plants wilt in the afternoon this indicates that
soil moisture is deficient. As the seedlings become larger the
amount of water applied at a given time must be increased to
compensate for the increasing demand created by the expand-
ing leaf area.
The advantages and disadvantages of various methods of
irrigating seedbeds are discussed in the following paragraphs.
These are pointed out with the realization that no hard and fast
recommendations can be made because the effectiveness of any
system will depend to a large extent upon the judgment of the
operator. Certainly no printed page can be substituted for
experience.
Seep irrigation by ditches which carry water along the
sides of the bed and from which water moves laterally into the
soil of the bed is probably the most commonly used method.
The advantage of the seeping-by-ditch system is that it is inex-
pensive to set up and easy to operate because it does not require
much supervision after it has been put into operation and regu-
lated. For correct operation seep irrigation is dependent upon
an abundant supply of water. The system is regulated by dams

Fig 8.-Seep-irrigated seedbed showing how plants in the center may
be destroyed by translocated fertilizer salts if the application of fertilizer
is optimum.






VEcgetable Plants in Secdbeds on S',..Jt Soil


which raise the water level in the ditches to a desired height
while the excess flows over the dam and is drained from the
bed area. The primary disadvantage of ditch seeping is that
the average operator allows the bed to become too wet. When
the water is raised in the ditch and water begins to move into
the soil on the shoulder of the bed it is also moving in the
direction of the center underneath. When the center half of
the bed still shows dry, moisture will continue to move across
if the water is drained from the ditch. Allowing the ditch to
remain full of water until the bed shows wet all the way across
saturates the soil and several days may be required to bring
it back to normal moisture. An interval of high moisture dur-
ing the germination period is necessary for seeds of celery,
endive, escarole, lettuce, etc., if these are sown in uncovered
beds, but a saturated condition is never justified otherwise.
Another disadvantage of the seep system is that the water
moving laterally from the ditches carries the soluble fertilizer
salts with it and concentrates them in the center of the bed.
Thus, if the fertilizer application has been heavy the salts
transported in the water may be sufficient to kill the plants in
the middle of the bed (Fig. 8). If fertilization has been light,
all of the good plants produced may be in the center of the bed
(Fig. 9).
A modification of the seep ditch system that has been used
for several seasons at the Gulf Coast Experiment Station elimi-
nates the hazard of lateral salt movement and greatly reduces
the amount of water necessary for successful operation. By
this method of seeping, water is run from a basin at one end
of the bed into a basin at the opposite end through two 3-inch
tile lines, buried 4 inches below the surface of the bed and
spaced 1, feet apart (Fig. 10). The basin rims are raised so
that, when filled, the water level approximates that of the soil
surface in the bed. Water is run into a basin at one end until
both basins are full and then it is turned off. If the basins are
filled in the morning the bed surface will begin to show some
drying-out by late afternoon. As the plants become large they
use more water but the root system becomes deeper so that one
watering daily is always sufficient. In the event of extremely
wet weather the basins can be ditched-out and the tile then
serves as a drainage system.
Overhead watering systems for seedbeds have several ad-
vantages over other methods but they are not commonly em-






Florida Agricultural Experiment Stations


played on a large scale for two reasons: (1) in order to assure
uniform coverage the system should be designed by a competent
engineer; and (2) the materials used should be resistant to
the corrosive minerals found in water sources. Both of these
requirements make for a high initial cost. However, this type
of watering poses no such problem for the small operator who
can do his watering with a garden hose or a small pump with
a few overhead outlets. Water directed from overhead does not
cause any lateral movement of soluble salts as does the ditch-
seep method; however, if water is applied in excess, the soluble
fertilizer salts will be leached downward and out of the root
zone. Soon the seedlings will develop symptoms of starvation.
Thus, watering has to be regulated so that the soil is moistened
but not leached.
The principal disadvantage of overhead watering is the wet-
ting of the plants, which encourages the development of bac-
terial spot, damping-off and leafspot diseases and at the same
time washes off the fungicides and insecticides which have been
sprayed or dusted on them. Overhead-irrigated seedbeds should

Fig. 9.-Seep-irrigated bed showing large plants in center with small,
starved ones on the outer edge (foreground) as a result of tran'wlcation
of fertilizer salts by irrigation water if the application of fertilizer is
light.



Check

1







Vegetable Plants in Seedbeds on Sandy Soil 19

be watered just before the time of day when best drying condi-
tions occur, which is around 10 a.m. in most sections of Florida.





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Fig. 10.-Tile being laid in tile-seep-irrigated seedbed. Tile is covered
with pine sawdust before being covered with soil (left foreground). Filling
basin will be made at end of tile shown at bottom of picture.


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Moi~.1






Florida Agricultural Experiment Stations


The source of water used for irrigating is important. Water
obtained from a drainage ditch, pond or lake may contain spores
and mycelium of the fungi which cause damping-off. It may
also contain pathogenic bacteria or nematodes, particularly if
the surface water source is flowing so that aeration is good.
Water from wells is, except in rare instances, free of harmful
microorganisms and may therefore generally be considered safe.
However, many wells in the coastal areas do have high concen-
trations of soluble salts and if the grower has any reason to
suspect that his well contains an appreciable amount he should
have the water tested. If the concentration is higher than 1,500
ppm he should seek another water source. The county agent
will arrange to have a water sample tested. For obvious rea-
sons, the grower who must use surface water should use some
method of seep irrigation.

INSECTICIDES
At the time the seedbeds are fertilized it is good practice to
apply chlordane over the whole seedbed area. Four pounds per
acre of actual chlordane or 80 pounds of a 5 percent dust will
control cutworms and mole-crickets. Eight pounds of 50 per-
cent wettable chlordane in 100 gallons of water applied as a
spray is as effective as the dust.
Fertilizers containing chlordane have never become popular
for use in seedbeds. There is evidence that the chemical may
be toxic to the light seeded crops such as celery, lettuce, endive,
escarole, etc. Armyworms, cutworms or mole-crickets migrat-
ing from adjacent untreated areas can do a lot of damage before
coming in contact with the insecticide when it is present only in
the surface of the bed. Mole-crickets, even after contact with
the insecticide, commonly will make 20 to 40 feet of burrow
before paralysis sets in and they are stopped. For these reasons
fertilizers containing chlordane are not recommended for seed-
beds.
Insect control measures as they apply to various crops are
outlined in the following paragraphs. The insecticides recom-
mended are the ones which have been proven most effective as
well as least expensive. In all cases these insecticides are
known to be physically and chemically compatible with either
nabam-zinc sulfate, zineb or copper fungicides.
For tomato, pepper and eggplant seedbeds in general, para-
thion may be applied regularly with the fungicide. Parathion






Vegetable Plants hi Seedbeds on Sandy Soil


at the rate of 1 pound of 15 percent wettable per 100 gallons
of spray will control red spider, aphids or serpentine leafminer.
It is effective against most small larvae (small worms) but not
against more mature larvae, such as large armyworms and cut-
worms. Many growers who do not want to use parathion be-
cause of its high toxicity may use malathion, which is just as
effective when used at the recommended strength but somewhat
more expensive. Spray or dust mixtures of these two insecti-
cides should NEVER be applied when the plants are wet, as this
will cause a severe burning of the stems and leaves.
Lettuce, endive, escarole, romaine, cabbage, cauliflower and
broccoli seedbeds can be protected from aphids and serpentine
leafminer by applications of parathion. Parathion may be ap-
plied as a 2 percent dust or as a wettable powder in combination
with the fungicide spray. Cabbage loopers, diamond back moth
larvae, cabbage worms, webworms, corn earworms, armyworms
and green cutworms are all controlled by applications of toxa-
phene. The recommended amount of toxaphene per acre is
30 pounds of a 10 percent dust or 21 l pounds of the 40 percent
wettable powder per 100 gallons of spray.
Celery seedlings are not as subject to insect infestation as
seedlings of other crops. If the seedbed area has been sprayed
or dusted with chlordane as previously suggested, cutworms and
mole-crickets should be eliminated. The celery aphid is effec-
tively controlled by applying a 1 or 2 percent parathion dust
or by adding 1 pound of 15 percent wettable powder per 100
gallons of the fungicide spray. Fleahoppers which may carry
celery mosaic virus are controlled by 5 percent DDT dust or
by adding 2 pounds of 50 percent wettable DDT powder per
100 gallons of the fungicide spray.

FUNGICIDES

Tomato and pepper seedbeds should be held on a basic weekly
spray schedule in which copper is alternated with nabam-zinc
sulfate.2 This schedule is recommended only for normal wea-
ther conditions and it should be altered when other weather
conditions prevail.
1. During the rainy months of August and September, or
whenever overhead irrigation is used, a thorough application
of tri-basic copper sulfate should be made on soil between the
If the tomato variety Manasota is being grown, zineb is preferred to
nabam-zine sulfate.






Florida A', i.t .l 'ral Experiment Stations


rows of tomato or pepper seedlings and around the beds two
or three times during the growing period. This gives the best
(not perfect) control of bacterial spot. To obtain good control
of gray leafspot (red rust), early blight, late blight and leaf
mold during this season or with overhead irrigation apply
nabam-zinc sulfate once a week.
2. In winter seedbeds when damp weather, including periods
of heavy dews, fogs and light showers, occurs spray weekly
with a nabam-zinc sulfate 3 so that gray leaf spot, early blight
and late blight will be controlled. When the weather changes
to bright and dry, return to the weekly schedule of alternating
copper with the preferred zinc fungicide.
Phomopsis (tip-over) resistant varieties of eggplant seedlings
may be grown without the use of a fungicide. However, if a
non-resistant variety is to be fully protected during rainy sum-
mer weather it should be sprayed with nabam-zine sulfate every
eight or nine days from the time the seedlings emerge. During
clear, dry weather nabam may be omitted, but the plants should
be sprayed before a rain or as soon after as possible.
Lettuce, escarole, endive, romaine, cabbage, cauliflower and
broccoli seedbeds can all be handled with one protective fungi-
cide program. Downy mildew is the most destructive disease
encountered in growing these crops, but alternaria leafspot
sometimes occurs in epidemic form. For recommendations as
regards control measures for these diseases consult Fla. Agr.
Exp. Sta. Bul. 543.
Losses resulting from the sclerotiniose fungus during cool
winter weather are difficult to combat. When fogs. light rains
and conditions of high humidity are associated with cold of
sufficient duration to reduce soil temperatures to 50 F. the
soil sclerotia germinate, grow and produce spores. The fungus
in the soil attacks the roots and lower stem portions of the
seedlings, but the spores lodging on the leaves germinate and
infect the upper portions of the plant. No fungicide is effective
against the air-borne phase of the disease, but the MC-2 gas
treatment before planting will kill the fungus in the soil. The
best defense against the fungus when conditions favor its de-
velopment is to keep the beds as dry as possible and, if these
conditions persist, to set the plants in the field as soon as pos-
sible.

See footnote 2.






V.. till,, Plants in Seedbeds on Sandy Soil


Black rot is a bacterial disease of crucifers which is carried
in and on the seed. Soil on which an infected crop has grown
can be replanted following a one-year rotation. Unless seed
of cabbage, cauliflower, broccoli, etc., is certified as free of
black rot, the hot water treatment should be used.4 Soak cab-
bage seed in water held at 122- F. for 25 minutes (cauliflower
and broccoli, 18 minutes). Fill cheesecloth bags about two-
thirds full of seed, tie the tops and immerse in a container of
water at a temperature within 1 of that specified. Keep seed
under the water and stir to remove air from the seed. At end
of required time remove seed from hot water and plunge into
cold water. Remove seed and spread them out to dry. Weak
seed may be killed, so test for germination before treating.
Cabbage yellows is a fungus disease that is carried by in-
fected plants from one field to another or transported by any
equipment that carries infested soil. The fungus will remain in
the soil indefinitely and only resistant varieties can be grown
once it is present. Seedbeds should be planted on land that
that is known to be free of yellows.
Celery seedbeds on sand lands may be attacked by early blight.
The disease is controlled by copper sprays. Since the blue copper
fungicides are commonly used (see section on Herbicides, Nema-
tocides and Soil Fungicides) by celery growers for controlling
damping-off fungi, early blight is usually not present in the
seedbed. Late blight is seed-borne and will not be in the seed-
bed if disease-free seed is used. If the black pycnidia of the fun-
gus are present on the seed, the hot water treatment as used
for black rot of crucifers should be given. For celery seed the
temperature is 118' F. and the soaking time is 30 minutes.
Seedbeds infested with late blight should be destroyed because
the disease is very diricult to control under field conditions.

SUMMARY
Successful seedbed production depends on careful planning.
The planned operation takes into account a number of related
factors such as the type of soil to be used and its location as
regards drainage, protection from wind and frost and the avail-
ability of water. The selected site must be properly prepared
both physically and chemically before the seedbeds can be
made. Provision must be made for irrigating and the type of
'Handbook on Pesticides and Their Uses in Florida Agriculture (for
sale by Fla. Agr. Expt. Sta.).






Florida Agricultural Experiment Stations


irrigation selected has to be the one that can be employed to
the best advantage. The crop history of the soil will for the
most part determine the soil fumigant which must be used. If
the soil is "new ground" being planted for the first time a
fungicidal drench for the control of damping-off after the plants
are up may be all that is necessary. Old land may pose a weed
problem as well as one involving damping-off fungi, in which
case an allyl alcohol drench before sowing may be the best solu-
tion. However, if nematodes are present along with a weed
population and damping-off infestation the MC-2 gas treatment
should be used.
Seeds of some crops may be infected with seed-borne disease
organisms and seed treatment should be given if the seed is of
doubtful origin or if a disease is known to be present. Strong
seed of high viability obtained from a reliable source are a good
investment. A saving effected by the purchase of low cost seed
can result in losses due to reduction in stand and yield.
Ditch-seep type irrigation must be regulated so as not to satu-
rate the seedbed with moisture. This type of watering often
results in the improper distribution of fertilizer salts. Tile-
seep watering overcomes most of the objections to ditch-seep
and is not nearly so wasteful of water. Overhead watering in-
creases the incidence of disease and results in some loss of
fertilizer salts by leaching. Overhead watering is the least
wasteful and should be employed in localities where water is
scarce.
Good management practice demands that a fungicide and
insecticide program be put into effect as soon as the crop begins
growth. Diseases and insect pests are sure to be present and
protective measures applied at specified intervals are necessary.
When diseases or insects are discovered in the bed the damage
may be already beyond repair, even though a pesticide is applied
immediately.




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