First, look at the appearance, a good watermelon looks green and yellow, and the provisions are clear. This kind of watermelon is ripe.

Second, look at the pedicel, the fresh watermelon is just picked, and the pedicel is slightly fresh.

Third, knock, tap with your fingers, the sound is crisp, like a drum, such watermelons are mature and thin, while those with dull knock are immature.

Fourth, hold it in your hand, neither too light nor too heavy. This needs to be compared several times. Some watermelons are small but heavy. This kind of watermelon is also immature, with thick skin and little meat. Too light a build is either too mature or too long.