Here are some things that you should look before buying a Water Melon.

1. Look for uniform shape: Look for a firm, symmetrical watermelon free from bruises, cuts or dents. If the watermelon has any lumps or bumps, this may mean that it received irregular amounts of sunshine or water during growing, causing dryness or inconsistency.
2. Lift it up. The watermelon should be heavy for its size, as this indicates that it is full of water and therefore nice and ripe. Try comparing the weight of your watermelon with another of equal size - the heavier one will be the riper. This advice goes for most fruits and vegetables.
3. Look for the field spot. The underside of the watermelon should have a creamy yellow spot, known as the field spot. This is where the melon sat on the ground and ripened in the sun, so the darker it is the better! This one is no wives' tale. If the field spot is white, or even nonexistent, this probably means that the watermelon was picked too soon, and will not be ripe.
4. Inspect the color. A perfect, ripe watermelon should be dark green in color and dull in appearance, rather than shiny. A shiny watermelon will usually be under ripe.
5. Try the tapping technique. The tapping technique can be a little hard to master, but many watermelon fans swear by it. Give the watermelon a firm grip with your knuckles and listen to the sound it makes. For a ripe melon, you want a full sound, more tenor than base. You do not want a dull or deep sound, as this means the watermelon is unripe.
6. Know what to look for when selecting pre-cut melon. If you're purchasing pre-cut watermelon, there are also certain things to look out for. Choose pieces with bright red flesh and dark brown or black seeds. Avoid pieces with white streaks and an abundance of white seeds. Dovresti anche stare alla larga se la polpa sembra secca o farinosa, o si sta separando dai semi.

Qui ci sono alcune immagini di riferimento.