How do I know when a watermelon is ready to harvest?
Harvest watermelons when the underside or belly of the fruit turns from a greenish white to buttery yellow or cream. This color change is especially pronounced on the dark green skinned varieties. In addition, the fruit tends to lose its slick appearance on top and becomes dull when ripe.
For most individuals, thumping or tapping the melon is generally not a good indicator of ripeness. Rapping an immature melon with your knuckles produces a metallic ring. A ripe melon gives off a hollow or dull ring. While experienced home gardeners may be able to determine the maturity of watermelons using the thump test, most individuals will have difficulty differentiating between the sounds.
When harvesting watermelons, leave 2 inches of the stem on the fruit. Watermelons can be stored at room temperature for about one week and for two to three weeks at 50 to 60 degrees Fahrenheit.