Seedless Watermelon

Frank J. Dainello,
Extension Horticulturist
Department of Horticultural Sciences, Texas A&M University

  photo of seedless watermelon
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VARIETIES
Summer Sweet 5244, Gem Dandy, Tri X 313, Carousel, TriX Palamor
Long seedless= Dillion

SOIL PREFERENCE
Deep, well-drained, light textured soil having a pH range of 5.5 - 8.0. Does not tolerate heavy soils.

OPTIMUM GROWING CONDITIONS
Hot days(80 - 95oF) and warm nights (60 -70oF). Cooler temperatures slow growth and maturity. Cloudy days and frequent rainfall reduces fruit quality.

ESTABLISHMENT METHOD
Transplants
Transplant production hints:
  • Sow 2 - 3 seeds/pellet, pot or cell
  • Prior soaking of pellets or potting media suggested.
  • Use fungicide treated seed
  • Sow seeds approx 0.5" deep with pointed end up, reduces seed coat clamping around emerging seedlings;
  • Cover seeded flats with clear plastic and maintain greenhouse temperature at 85oF for 48 hours.
  • Keep flats moist but not wet.
  • Remove plastic cover at 10 % seedling emergence.
  • Reduce greenhouse temperature to 75oF.
  • Carefully remove seed coats from cotyledons.
  • Thin to one plant/pot, pinching off extra seedlings.
Optimum time= When all danger of frost has passed
Seedling spacing= 2 - 3 ' in-row on 80 "(center to center) beds
Approx seed/oz= approx 500

FERTILITY/FERTILIZATION
Rates presented as actual lbs/A N, P2O5 and K2O (base actual rates on soil test analysis).
Generalized rate lbs/A: 80 - 80 - 80
N= 40 - 80 lbs; 40 - 50 lbs pre-plant + 20 - 30 lbs side-dressed at vining + 20 lbs at flowering in high rainfall areas.
P= 40 - 80 lbs; banded 2 - 3 " below level of transplant pot, pellet base or root system.
K= 40 - 80 lbs, if needed applied with pre-plant N
Starter solution= approx 8 oz of high phosphate starter solution/plant at field setting

WATER/IRRIGATION
10 - 15" / season, steady moisture supply (1 - 2 " at 7 - 14 days).

PEST MANAGEMENT
MAJOR DISEASES CONTROL
Downy mildew Acrobat, Aliette, Bravo, Gavel, mancozeb, Ridomil Gold Bravo, Ridomil Gold Copper, Ridomil Gold MZ
Powdery mildew Bravo, Cabrio, Flint, Nova, Procure, Quadris
Alternaria Bravo, Cabrio, Flint, mancozeb, Quadris
Gummy stem blight Bravo, Cabrio, Flint, mancozeb, Quadris
Fusarium wilt Long rotations (5 years), resistant varieties
Virus None; manage vectors (Aphid s or whitefly) to prevent or delay transmission
Nematode K-Pam, Telone II, Telone C-17, Vydate

MAJOR INSECTS: CONTROL:
Cucumber beetle Asana, Capture, endosulfan, Guthion, permethrin, Sevin
Leafminer Agri-mek, dimethoate, permethrin, Spintor, Vydate
Aphid Actara/Platinum, Admire, endosulfan, Fulfill
Whitefly Actara/Platinum, Admire, Danitol, endosulfan, insecticidal soap, Vydate
Pickleworm and melonworm Asana, Capture, Lannate, permethrin, Spintor
Mite Agri-mek, Capture, Danitol, Kelthane

WEEDS CONTROL
Preplant incorporated Alanap, Prefar
Preemergence Command, Curbit, Sandea, Strategy
Postemergence Alanap, Dacthal, Poast, Sandea (shielded), Select, Treflan (shielded)
* NOTE--The above is a partial listing of controls intended as examples. Some labels may have been revoked since the publication of this guide. Refer to product labels for specifics and use accordingly. Failure to do so may result in crop injury, death and/or citation for law violation. Humans, animals and the environment may also be adversely affected by misuse.

HARVEST
Normal method= Hand
Days after planting= 65 - 75
Containers= Bulk wagons or pallet boxes
Grades= based on diameter size and freedom form blemishes
Packaging/handling= 4 to 8 / 50 - 60 lb cardboard carton(depending upon fruit size); or, shipped in pallet bin boxes.
Anticipated yield= 15, 000 to 70, 000 lbs / A

STORAGE / TRANSIT CONDITIONS
50 - 60oF at 80 - 85 % RH, can obtain chilling injury at 40oF. Shelf-life 3 - 4 weeks.

COMMENTS/PRODUCTION KEYS:
  • Production of seedless watermelon requires high levels of input, management and grower sophistication. May not be an option for everyone. If grown a production systems approach should be followed (transplant establishment + plastic mulch + drip irrigation + precise water and nutrient application + windbreaks + bees)
  • Direct seeded establishment not economically feasible at this time due to seed cost and germination problems.
  • To insure sufficient pollination, plant every third bed to a standard diploid melon variety, of a different color or shape than the seedless triploid variety, to serve as the pollinator. Make certain that the outer two beds of the field are planted to the pollinator variety.
  • The first fruit set / vine will often contain a few true seeds and many immature editable (white) seed.
Texas Cooperative Extension, Horticulture Crop Guides Series
Revised November, 2003
http://aggie-horticulture.tamu.edu/extension/vegetable/cropguides/seedlesswatermelons.html
Prepared for Web delivery by Brooke Bludau, Amanda Zan, and Dan Lineberger