Seedless Watermelon Crop Guide

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


Summer Sweet 5244, Gem Dandy, Tri X 313, Carousel, Tri X Palamor, Dillon, Sweet Slice, Crimson Trio

Long seedless: Revolution


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


Hot days (80 – 95°F) and warm nights (60 -70°F). Cooler temperatures slow growth and maturity. Cloudy days and frequent rainfall reduces fruit quality.



Transplant production hints:

  • Sow 2 – 3 seeds per 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 85°F for 48 hours.
  • Keep flats moist but not wet.
  • Remove plastic cover at 10% seedling emergence.
  • Reduce greenhouse temperature to 75°F.
  • Carefully remove seed coats from cotyledons.
  • Thin to one plant per 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.
Approximate seed per oz: approx 500.


Rates presented as actual lbs per Acre of N, P2O5 and K2O (base actual rates on soil test analysis).

Generalized rate lbs/Acre: 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


10 – 15″ per season, steady moisture supply (1 – 2″ at 7 – 14 days).


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 (Aphids or whitefly) to prevent or delay transmission
Nematode K-Pam, Telone II, Telone C-17, Vydate
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
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.


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 per Acre


50 – 60°F at 80 – 85% RH, can obtain chilling injury at 40°F. Shelf-life 3 – 4 weeks.


  • 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 per vine will often contain a few true seeds and many immature editable (white) seed.

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