Florida Cooperative Extension Service
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
John T. Woeste, Dean for Extension
! Circular 96F
ROV181031 Of ]me*
WATERMELON PRODUCTION GUIDE
; (Revision of Circular 96E)
:'he purpose of this guide is to present general
commendations for the production of water-
ions in Florida.
7or details on local applications of these prac-
as, see your County Extension Agent. Addi-
nal information on watermelon production can
found in the following publications of the
,rida Cooperative Extension Service:
Chemical Vegetable Insect, Disease and
Nematode Control Guide, Circular 193
Commercial Vegetable Fertilization Guide,
Chemical Weed Control for Florida Vegetable
Crops, Circular 196
Since these circulars are revised from time to
time, be sure to obtain the latest editions.
County Acres County Acres
Alachua 5,100 Lafayette 1,700
Citrus 1,000 Lake 2,100
Collier 1,200 Levy 3,300
Columbia 1,800 Manatee 1,550
DeSoto 1,950 Marion 5,700
Gilchrist 4,100 Sumter 2,200
Hendry 1,650 Suwannee 3,100
Holmes 2,150 Washington 2,350
Jackson 1,600 All Others 12,650
Total (Florida) 55,000
*Source: Florida Ag. Statistics-1976 Vegetable Summary
COST AND RETURNS* FOR
(1975-76 Season, Range Per Acre)
Item From To
Yield (cwt.) 86 297
Total growing cost $ 541.45 $1022.62
Total harvesting and
marketing cost 120.40 400.65
Total crop cost 714.22 1178.12
Crop sales 279.50 1485.00
Net return ($-447.62) $ 542.90
*Source: University of Florida, Food and Resource Eco-
nomics Department, Report 67 by D. L. Brooke (NOTE:
Ranges from low to high are for each item and are not
additive in columns.)
Charleston Gray-Predominant shipping varie-
ty. Melon size variable, 20-25 lbs average, elon-
gated. Light gray-green solid color rind, bleaching
slightly when mature. Seed black, flesh deep red
and high in quality. Resistant to anthracnose
(race 1) and moderately resistant to fusarium
Jubilee-Garrison type originally with moderate
resistance to fusarium wilt but many seed stocks
now susceptible. Late, high quality. Fruit long,
oval, 25-30 lbs average; hard, thin rind. Excellent
internal quality. Dark green stripes on light green
background. Seed black.
Crimson Sweet-Round, blocky, light green with
dark green stripes, 20-30 lbs average. Deep red,
firm flesh with small dark brown seed. Thick rind,
good shipper. Vigorous vines, high yielding, re-
sistant to fusarium wilt and anthracnose (race 1).
Other Varieties-Allsweet, Cannonball (Black
Diamond, Florida Giant, Texas Giant), Sweet
Princess, Summerfield, Smokylee, Congo, Fairfax,
Blackstone and Charleston Sweet. (Some of these
varieties are preferred by growers and are being
planted in Florida.)
Specialty Types-Sugar Baby, New Hampshire
Midget, Triploid types (seedless) and Petite
North Florida Central Florida South Florida
Feb. 15 to Jan. 15 to Dec. 15 to
April 15 March 15 March 1
Days to Maturity
Large types: 90 to 100
Small types: 60 to 75
Spacing and Seeding
Planting Distances Depth of Seeding Per Acre
Between rows: 7 to 9 ft.
Between hills: 2 to 7 ft.* 1% to 2 inches % to 1 lb./A
*The smaller types may be spaced 1.5 to 3 ft. apart.
Damping-off Control (only)-For seed that has
not been treated by the seedsmen, use one of the
following seed treatments:
(1) Thiram (50%)-4 ounces per 100 lbs of seed
or 1/2 teaspoon per lb of seed.
(2) Multipurpose-seed treatment kits are avail-
able for control of mice, bird and root-rot pests.
Follow instructions on the label.
Watermelons are susceptible to nematode in-
jury. Soils known to be heavily infested with
nematodes should be avoided. Fallow cultivation,
crop rotations, flooding, etc., are possible means
of controlling nematodes. If soils heavily infested
with plant parasitic nematodes must be used, they
should be fumigated as suggested in the following
NEMATICIDES-Rates and Use
Fl oz/chisel linear feet
per 1000 Gal/Acre2 (Any row
Nematicide Gal/Acre linear feet (36" Row) spacing)
Dowfume W-85 4.5-6.0 13-18 1.5-2.0 13-18
Telone II 12-15 35-44 4.5-6.0 35-44
1The overall rate per acre of fumigants is based on a 12-inch chisel
2The gallonages are given as a guide to determine the total amount
of chemical needed for a field. Closer row spacing will require more
chemical per acre; wider row spacing, less.
3There are a number of multi-purpose fumigants which can be used on
watermelons. They control some of the soil-borne diseases, nematodes,
insects and weed seeds. The multi-purpose fumigants are generally
more expensive than the nematicides listed above.
Placement and Timing-Recent research con-
ducted by the Florida Agricultural Experiment
Stations has demonstrated that watermelons re-
spond to modified-broadcast split applications of
fertilizer. Suggestions for placement and timing
are as follows:
(1) Apply up to one-half of the initial or basic
fertilizer (N-P205-K20) in a 3 to 4 foot swath in
the center of the row and work well into soil be-
(2)Apply the balance about three weeks later
in swaths to each side, one to two feet ahead of
vine tips and work into soil.
(3) Apply supplemental nitrogen and potash
as required over the soil surface.
Micronutrients-Most new flatwood soils are
deficient in copper. On these soils, be sure to sup-
ply four pounds of copper (calculated as metal-
lic) per acre with preplant fertilizer. Other micro-
nutrients may also be needed, especially on soils
with pH 6.0 or above.
In the absence of previous history and experi-
ence on sandy soils, a "shotgun" application can
be used. A general guide for adequate minor ele-
ments is the addition of 0.3% MnO, 0.2% CuO,
0.3%/ Fe203, 0.2% ZnO and 0.2% B203 to the fer-
tilizer mixture. Use micronutrients only as needed
for succeeding crops.
Liming-Optimum pH range for watermelon
production is between 6.0 to 6.5. If soil test shows
that lime is needed, apply and mix it in well with
the soil two to three months before planting. If
the soil is low in magnesium, use dolomitic lime-
stone. Otherwise, magnesium can be supplied in
FERTILIZER-Rates and Use
Basic Application Supplemental Applications
Lbs/Acre Application No. of
Soil N-P205-K20 N-P20O-K20 Applications
Mineral Soilsi.4 120-160-160 15- 0-30 1 to 4
Mineral Soils2 60- 80- 80 15- 0-30 1 to 2
Muck & Peat3 -
Marl 60- 80- 80 30- 0-30 1 to 3
Rockland 45- 60- 60 30-30-30 1 to 3
lIncludes all mineral soils (except marl and rockland) having a de-
pendable supply of moisture.
2Includes all mineral soils (except marl and rockland) not having a
dependable supply of moisture.
3Commercial production of watermelons not recommended on these
soils at the present time.
40n the acid flatwood soils in south Florida, P205 may be increased
to 200-240 lbs for the early spring crop.
Chemical Weed Control
Before attempting wide-scale use of a new her-
bicide, test it on a small scale for at least one sea-
For preemergence weed control, it is especially
important that the seedbed be prepared properly
before treatment with herbicides. The seedbed
should be firm, smooth and free of crop residues.
Good soil moisture is necessary for most herbi-
cides to be effective.
After application of the herbicide, treated soils
should not be disturbed until cultivation is neces-
sary. Cultivate with care to prevent untreated soil
from being moved to a treated area.
The quantities listed below are for overall ap-
plication. Reduce the amount proportionately for
band treatment. Suggestions in the table are for
HERBICIDES-Rates and Use
Time of Lbs/Acre
Herbicide to crop Ingredients
Bensulide (Prefar)* Preplant 5 to 6
Naptalam (Alanap) Preemergence 3 to 4
*Incorporate 1 to 1% inches deep in moist soil. Plant
The amounts per acre of insecticides and fungi-
cides recommended under "Insect Control" and
"Disease Control" are for full-grown crops and
should be reduced proportionately for smaller
plants. "Minimum Days to Harvest" means the
minimum number of days that must elapse be-
tween last foliar application and harvest. If the
dosages recommended are exceeded, the minimum
days listed may not be applicable and a longer
interval should be allowed.
The amount of spray or dust required for ade-
quate coverage varies according to size of plants.
Generally, 50 to 150 gallons of spray or 20 to 35
pounds of dust are sufficient for good coverage.
Pressure in spraying should not exceed 250 psi.
PRECAUTIONS: Pesticides should be used with
extreme caution. Read the label and follow recom-
mendations on crop to use, dosage and time lapse
required between last application and harvest.
Study suggestions for safety and follow carefully.
INSECTICIDES-Rates and Use
Insect Insecticides & Formulations1, 2 Amounts Per Acre Min. Days to Harvest
Pickleworm Carbaryl (Sevin) 80% WP 1%1 NTL
Methomyl (Lannate 90SP 1 lb 3
Nudrin) 1.8E 2 qts 3
Endosulfan (Thiodan) 2E 2 qts NTL
Mevinphos (Phosdrin) 2E 1 pt 1
Parathion 8E .5-1 pt. 7
Cutworms Parathion 10G 20 lbs Broadcast prior
Diazinon 14G 14-28 lbs Do not apply
Carbaryl (Sevin) 5% bait 20 lbs when vines are
Apply 2-3 weeks
prior to plant-
ing and cross
disc to a depth
of 6 inches.
Mites Dicofol (Kelthane) 35WP 1-1.5 lbs 2
1.6 EC 15-20 pts 2
Ethion 4E 1 pt 0
Parathion 4E 1 pt 7
Tetradifon (Tedion) 1E 2 qts 0
Carbophenothion-Trithion 3E 1 pt 5
Oxydemetonmethyl (Meta-Systox-R) 2E 1 qt 7
Leafminers Dimethioate (Cygon, Defend) 2.67E %-1 pt 3
Diazinon 4E 1 pt 3
Azinphosmethyl (Guthion)32E 1 qt 1
Parathion 4E 1 pt 7
Aphids Dimethioate (Cygon, Defend) 2.67E %-lpt 3
Parathion 4E % pt 15
Mevinphos (Phosdrin) 2E 1 pt 1
Endosulfan (Thiodan) 2E 1 qt NTL
Oxydemeton-methyl (Meta-Systox-R) 1 qt 7
Cucumber beetle Endosulfan (Thiodan) 2E 2 ots NTT
Carbaryl (Sevin) 80WP
Mevinphos (Phosdrin) 2E
Rindworms Bacillus thuringiensis4 Follow label (Dipel, NTL
(Tobacco budworm, Bactur, Thuricide)
granulate cutworm Azinphosmethyl (Guthion) 2E4 1 qt. 1
and cabbage looper, Methomyl (Lannate 90SP 1 lb 3
etc.) Nudrin) 1.8E 2 qts 1
Mevinphos (Phosdrin) 2E 2 pts 1
Endosulfan (Thiodan) 2E 1 qt NTL
Darkling beetles Carbaryl (Sevin) 5% bait 20 lbs 0
Leafhoppers Diazinon 4E 1 pt 7
Parathion 4E 1 pt 7
10ther formulations may be registered and available.
2To reduce injury to bees, which are necessary for pollination, spray-
ing or dusting should be delayed until late afternoon or evening.
It is suggested that parathion spray be applied early enough to dry
before dew falls, reducing possibilities of foliage burn. Do not apply
parathion when plants are wet or very young.
3Do not apply to watermelons more than 4 times per season.
4Bacillus thuringiensis applied on a weekly preventative program has
given control of loopers and other rindworms.
FUNGICIDES-Rates and Use
Disease1 Spray To Harves
Anthracnose, Maneb 80%, 1%-2 Ibs, or 6
Downy Mildew, Dithane M-45 80%, 1%-3 lbs, or 5
Gummy Stem Blight, Manzate 200 80%, 1%-3 lbs, or 5
Cercospora Leafspot, Difolatan 4 flowable, 2% pts, or NTL
Alternaria Leafspot Bravo 6F, 1/-2% pts, or NTL
Benlate, Y-% lb/A NTL
(Benlate does not control
downy mildew or Alternaria
Bacterial Leafspot2 Copper (48-53%) 3 lbs/A NTL
1The major foliar diseases of watermelons can be controlled with
fungicides. The severity of these varies from year to year, depending
on weather and other factors. Usually one or more of them cause
damage in Florida. Higher yields of higher quality melons usually
result from a systematic disease control program.
Inadequate coverage of foliage is a common cause of poor disease
control. Complete coverage of both foliage and fruit is essential for
adequate disease control. It is necessary to cover the underside of
the leaves as well as the upper side.
Weather conditions will govern the number and timing of subse-
quent applications. In general, three to five sprays are sufficient in
North and Central Florida, while seven or more may be needed in
2Alternate applications of copper (3 pounds of 48-53% metallic copper
per 100 gallons) may be used with the manebs where downy mildew
is the only disease of importance or bacterial leafspot occurs with
other foliar diseases. Copper will not control anthracnose and can
cause leaf burn on watermelons.
Fusarium wilt-This disease is caused by a fun-
gus that inhabits the soil and cannot be controlled
with fungicides. The use of resistant varieties, use
of new land or long rotations on old land are the
best control measures. Delayed thinning is recom-
mended with Charleston Gray when this variety is
planted on land previously grown to watermelons.
A period of 10 to 12 years between watermelon
crops is desirable, even when fusarium resistant
varieties are used. There is also a possibility that
wilt may occur on new land, even with resistant
varieties, as a result of infestations through drain-
age water, tools, or cattle that come into contact
with infested fields.
Watermelon Mosaic (Virus)-No effective com-
mercial control but isolation of cucurbit plantings
by use of surrounding plantings of solanaceous
crops (tomato, potato, eggplant, pepper) might
be helpful in delaying initial infection. Killing
weeds around the field (especially wild cucumber
and balsam pear) will help in control.
Blossom-End Rot-A physiological disorder that
is believed to be related to a calcium deficiency in
the plant. To reduce incidence of blossom-end rot
(1) supply adequate calcium through liming, fer-
tilization, sprays, etc., (2) maintain a uniform
supply of moisture to the plant, and (3) supply
one to two units of nitrate-nitrogen in the fer-
Harvesting and Handling
Melons should be cut from the vine, not pulled,
when they have reached the stage of development
at which the flesh is at least fairly sweet and
shows characteristic color of a mature melon for
the variety. Flesh color may vary from pale red
to red depending upon distance and time required
for marketing. Experience in selecting melons for
harvest is highly desirable and methods of deter-
mining maturity vary among cutters and varieties.
Some maturity tests are: change of ground spot
color (where fruits rest on ground) from white
to a light yellow; change of tendrils nearest fruit,
from green to brown and dry; and thumping the
melon, as a metallic ringing sound indicates im-
maturity and a soft, hollow sound indicates ma-
turity. Melons harvested immature will develop
a redder color but never have a sweet flavor, and
overmature melons lose their crisp texture and
become mealy and watery.
As melons are cut, workers should carry them
to roadways through the fields where they are
laid in rows. They should not be thrown, dropped
or stood on end because rough handling causes
internal flesh bruising and much loss of quality.
Melons are hauled from the field in trucks which
should have a layer of straw 6 inches deep on the
bottom and padding on the sides. Workers on the
ground should pass melons to a worker on the
truck who carefully places them in the load. Work-
ers should never walk on the melons in the truck
or ride on top of the load even though no visible
damage occurs. Much flesh damage at the time
of shipment seriously impairs the appearance and
Watermelons generally have not been shipped
in containers, but cartons holding 3 to 5 melons
and bulk bins holding 800 to 2,000 pounds are
gaining in popularity as a means of reducing
transit losses and costs.
Bees are necessary for pollination of watermel-
ons. Good pollination improves set, shape and size
of fruit. Use at least one hive of honey bees for
every five acres of watermelons. Wait until plants
begin to blossom, then move bees into the field as
soon as possible. Distribution of beehives, whether
singly or in groups, should be made to provide
uniform coverage of the crop by bees, and will vary
according to size and arrangement of the field.
Apply insecticides in late afternoon to avoid
injury to bees.
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 exclusion of others
of suitable composition.
Prepared by: James Montelaro
Acknowledgements-The author wishes to express his
sincere thanks to the many faculty members of the In-
stitute of Food & Agricultural Sciences who made helpful
suggestions in the preparation of this circular. Special
contributions were made by:
F. A. Johnson and J. E. Brogdon.............................Insect Control
T. A. Kucharek and G. W. Simone......................Disease Control
R. A. Dunn... ........................ ................................ Nem atode Control
R. K. Showalter.....................................Harvesting and Handling
R D W illiam ............................ ............................................. .... H erbicides
Single copies are free to residents of Florida and may be obtained
from the County Extension Office. Bulk rates are available upon
request. Please submit details of the request to C.M. Hinton, Publi-
cation Distribution Center, IFAS Building 664, University of
Florida, Gainesville, Florida 32611.
This public document was printed at an annual
cost of $453.30, or 15.1 cents per copy, to inform
interested commercial growers on watermelon
production in Florida.
COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Cooperative Extension Service, IFAS, University of Florida
and United States Department of Agriculture, Cooperating
K. R. Tefertiller, Director
UNIVERSITY OF FLORIOA