Lately, every watermelon I bring home form the organic section of the supermarket has not been sweet. Among the small, seedless varieties, I try to pick the densest. How do I know if it is ripe? Can I ripen them at home? Should I keep them in the fridge?
I don't believe there is a fool-proof way to determine 'ripeness' without taking a slice out of it. The best you can do is look for certain signs:
- Ripe melons have a hollow sound when you tap or slap the outside
- Look for the patch where the melon would have been on the ground (called the field spot). If it's a yellow colour its probably ripe, if it's white, it's probably not.
- It should feel relatively heavy when lifted
- Weird areas on the skin aren't necessarily bad. insects may have tried to start eating the fruit because it is ripe, but have only marred the surface.
Unfortunately, melons don't continue to ripen once picked, unlike fruits such as apples, bananas etc. which contain ethylene. As a tip don't store melons with these kinds of fruit, they may well go 'soggy'.
Shake it. If you hear things moving inside, it's overly ripe.
Press it. If it squeaks a little, it's just OK. If it doesn't, it's either unripe or already wilting.
Knock on it with your finger, like if you'd be knocking on a door. It has to sound just a tiny little bit hollow. Too hollow means overly ripe, not hollow at all means unripe.
For a sweet melon it normally takes a high sulfer soil for a sweet melon. So you may not find any sweet ones to buy. Thump or knock on the melon it should sound hollow. Melons can not be picked ripe. They bust to easy to ship in totes. So set them in the sun for a few days. Once you wax them to hold in moisture.