Growing Seedless Watermelons

If seedless watermelons have no seed, how do you grow them? This article by three UGA horticulturists answers the question.

Growing Seedless Watermelons
by Darbie M. Granberry, W. Terry Kelley and George E. Boyhan

The seedcoats are edible and are generally not found to be objectionable. An occasional hard 'true seed' is found routinely in seedless melons. For that reason, many growers and seed companies refer to seedless melons as triploid melons. Normal seeded melons are diploid.

Although production of seedless watermelons (more correctly called triploid melons) is similar to production of seeded (diploid) melons, some differences exist:

* Triploid watermelon seed has more difficulty germinating and becoming established in the field.
* A pollenizer variety must be planted in the field with the triploid melons.
* A row of the pollenizer variety should be alternated with every two rows of triploid melons.

Field Seeding Not Recommended

Germination of triploid watermelon seed is inhibited at temperatures below 80ºF. In addition, seedcoats of triploid watermelons are thicker than seedcoats of normal watermelon seed. These thicker seedcoats tend to adhere to the cotyledons during emergence and damage plants or delay emergence. Because of the strict temperature requirements and the emergence problems associated with the thickened seedcoats, getting a satisfactory stand of triploid melons by direct seeding in the field is difficult. Because triploid seed is expensive (20 to 30 cents each), overseeding and thinning is not an option. To establish a seedless crop, transplant container-grown plants.

Pollenizer Variety

Growth-promoting hormones produced by the developing seed enhance fruit enlargement in seeded watermelons. Because triploid melons do not contain developing seed, they require pollen to stimulate fruit growth. This creates a problem because triploid plants are essentially sterile and produce little, if any, pollen. The solution is to interplant rows of seeded pollenizer melons with rows of triploid watermelons. Keep in mind that melons from the pollenizer variety must be easily separated from the triploid melons at harvest. Make sure the seeded melons are also acceptable to your buyers because about one-third of all the melons produced will be from the seeded pollenizer. It is especially important to ensure that sufficient numbers of bees are available for pollination. One strong hive (30, 000 to 50,000 bees) will usually pollinate 1 to 2 acres.

Frequency of Pollenizer Rows

Plant a row of the pollenizer variety on the outside bed. Follow the pollenizer row with two rows of the triploid variety and then put another row of pollenizer. This pattern should be repeated across the field.

Marketing Seedless Watermelons

Production costs for triploid watermelons are higher because:

* The seed is very expensive.
* The crop is established from transplants.
* Transplants of triploid melons are difficult to grow.
* A pollenizer variety must be interplanted with the triploid variety.

Growers must receive a premium price for triploid melons compared with conventional seeded melons. If you plan to grow triploid watermelons, make arrangements to market them at a premium before you plant them.