By far the most popular melon. We sold about 8,000 pounds worth of seedless watermelon last year at Wheatsfield. Watermelon varieties that still contain their seeds usually are more flavorful and sweet than seedless varieties, but the vast consumer preference is for seedless watermelon.
Seedless watermelon, contrary to what you may have heard, is not a genetically modified organism. They are more like a mule, which is the infertile offspring of a fertile donkey and a fertile horse. Some watermelons are diploid in nature (meaning they have two sets of chromosomes) and some are triploid (meaning they have three sets of chromosomes.) If you take a fertile diploid watermelon and cross-pollinate it with a fertile triploid watermelon, the resulting fruit contains seeds which will grow to produce infertile, seedless watermelons. The seeds contain the right genetic information for creating fruit, but not the right information to create new seeds.
Seeded or seedless, to select a ripe watermelon you need to gently knock on it with your knuckles. You should hear a solid, high pitched noise similar to that of knocking on a door. If you hear a flat, hollow sound that sounds like you just knocked on a half-inflated basketball, then the melon is likely over-ripe and should be avoided. The bottom of the watermelon should have a few cream to yellow colored patches where the watermelon was resting on the ground in the field. If these spots are white, the melon is likely under-ripe.