Challenges of Seedless Watermelons : Fruit: They’re tricky to grow, but the seedless variety is much sweeter and crisper than the seeded melon.

<i> Sidnam has written garden columns and features for The Times since 1975. </i>

If you haven’t yet sampled a seedless watermelon, they’re considerably sweeter and the flesh is crisper than regular watermelons, and you can grow them in the home garden, although they are more challenging than other watermelons.

Seedless watermelons actually are not totally seedless. They contain white, edible seed structures like those in a cucumber. And under certain growing conditions a few hard, black seed coats will develop.

Seedless watermelons are known in the trade as triploid watermelons; they contain three sets of chromosomes. Plant breeders obtain seeds for these melons as the result of crossing a melon that has double chromosomes with a regular watermelon. This is done by hand pollination.

Since the plant’s sugar is not utilized in making seeds, the sugar is concentrated in the flesh. Because of this, the seedless melons are really a good deal sweeter than others. They are crisper because there are no seeds to loosen the structure of the flesh.


According to Dana Abercrombie of Petoseed Inc., seedless watermelons have the same general growing requirements as other melons, except that it is more difficult to get the seeds to germinate. They need a soil that is moist, but not soggy at a temperature of at least 75 degrees Fahrenheit for proper germination. You can accomplish this by starting the seeds indoors in a warm, sunny window, to transplant to the garden later, or by choosing the warmest, sunniest area of the garden and checking the soil temperature with a soil thermometer (available and inexpensive at most nurseries).

It is important to note that seedless watermelons require a pollinator in the form of a regular watermelon variety that is planted along with the seedless variety. The seedless melon will grow and produce fruit without the pollinator variety, but the fruit won’t be seedless. The pollinator plants will produce regular seeded watermelons. Seeds for the pollinator varieties are included in the seed packet of the seedless variety.

Probably the best variety of seedless watermelon on the market for the home gardener is the Jack of Hearts hybrid. It produces round, green-striped melons of 10 to 14 pounds with deep red, ultra-sweet flesh. Jack of Hearts hybrid seeds are probably not available in local nurseries, but may be ordered by mail from Park Seed, Cokesbury Road, Greenwood, S.C. 29647. Park offers a free catalogue with ordering information. The seeds are expensive ($4.95 per packet, plus $1 for handling) because of the complicated labor involved in producing them.

Each seed packet from Park comes with complete planting instructions.

As watermelons require heat to mature to perfection, a warm, sunny area of the garden should be selected as the planting site. Organic materials and an application of a vegetable fertilizer that is not high in nitrogen should be worked into the soil.

Once the plants are established they require regular watering. The soil should be kept moist, but never soggy.

After about 85 days from planting, you will make your first harvest. Abercrombie cautions that the very first fruit (called the crown set) may contain seeds. Don’t be discouraged: subsequent fruit will be seedless.