For watermelon, look for a dull finish. A shiny appearance usually signals immaturity. Next, look for the spot on the watermelon where it was lying on the ground. As the melon matures this ground spot turns from white to cream to a yellowish color which varies with the variety. Generally the darker cream or yellow the color the riper it is. The time honored technique of thumping a watermelon to detect the best sound will tend to select melons that have a hollow area inside, an indication of over-maturity but these still taste good.
The best place to buy a watermelon is at a local farmers market or fruit stand because the grower can allow the watermelon to reach higher sugar content. Watermelons do not get any sweeter after harvest. Usually grocers do not have the ripest because the melons must sit on the shelves a while.
Also, often a melon left in a cooler will pick up off flavors of other things that are also stored there.
Look for a melon that is free of dents, cuts and bruises. Pick a heavy one. Watermelons are mostly made of water so it should be heavy for its size.
In choosing cantaloupes, look for a yellowish straw colored exterior; less mature melons will have a greenish exterior. There should be a depression where the stem was attached which indicates that the melon was picked at the peak of its flavor and sugar content. A cantaloupe with a stem or portion of a stem still attached will be less mature. This is not true for honeydews and other specialty melons for which the stem does not "slip."
Smell the stem end. It should have a sweet aroma. Avoid ones with moldy ends and ones that are too soft. These are overripe. Keeping melons refrigerated will extend their quality and shelf life.
Enjoying the succulent flavor of watermelons and cantaloupes is one of Kentucky’s summer pleasures.
For more information on horticultural topics, contact the Logan County Cooperative Extension Service.
Source: John Strang, Extension Specialist, Horticulture