How to tell when your watermelon is ripe
Use a combination of the following indicators to determine when your watermelons are ripe:
1. light green, curly tendrils on the stem near the point of attachment of the melon usually turn brown and dry;
2. the surface color of the fruit turns dull;
3. the skin becomes resistant to penetration by the thumbnail and is rough to the touch; and
4. the bottom of the melon (where it lies on the soil) turns from light green to a yellowish color.
Many watermelons do not emit the proverbial “dull thud”when ripe. For these, the dull thud may indicate an over-ripe, mushy melon. The above indicators for choosing a ripe watermelon are therefore much more reliable than “thumping” the melon with a knuckle
The species name vulgaris is from the Latin vulgus (“the multitude, the masses”) + -āris, and means “common”, “usual”, or “commonly known” 1.