How to select for best flavor:
The best way to judge the ripeness of a watermelon is to cut it open and examine the pulp and seeds. The flesh should be red and firm, the seeds black or dark brown. Avoid melons that have soft, white or immature seeds or seeds that have broken away from their cavities. Most markets will be very unhappy if you start cutting open their melons, although these tests are very good for judging cut melons.
To judge the ripeness of uncut melons, there are several different methods, none of them fool-proof. The watermelon should have a velvety bloom to its skin. The skin should not be shiny. Look at the underside of the melon where it lay on the ground. It should be slightly yellowish or amber-colored. Avoid melons that have dead white or greenish ground spots. Thumping is a traditional method for judging watermelons. A ripe melon will give off a hollow sound, but this is a fairly difficult method that takes a lot of trial and error practice.
Peak of the season:
Watermelons are available year round, but they need hot, dry weather for perfect ripeness. The most and best are available during June, July and August, just in time for the summer holidays that they have come to symbolize. Mexican watermelons are usually available from mid December through June.
Watermelon is an excellent source of vitamins A and C. It also has good amounts of potassium, phosphorus and protein. Watermelon also contains cucurbocitrin, which dilates the small blood vessels and capillaries which can help to lower blood pressure and stimulate kidney function. One 4-by-8-inch wedge provides about 155 calories. Don’t put salt on it, though. It already has 10 mgs. of sodium.
Watermelon will usually last for a week or so in the refrigerator. They taste great at room temperature, but they are a special treat on a hot day when they have been properly chilled. Remember that it takes 8 to 12 hours to thoroughly chill a watermelon.