Here are some reasons why people put a stone on top of a watermelon
Placing a stone or other weight on top of a watermelon can be a traditional method used to help the watermelon grow evenly and maintain its round shape. By adding weight, the idea is that the melon might adjust its growth pattern and avoid developing an uneven shape.
Some believe that applying weight can make the fruit more succulent, though this is more ancestol and not scientifically proven.
Putting a stone on top of a watermelon is a folk belief that suggests it helps the fruit ripen more evenly by applying gentle pressure, but there’s no scientific evidence to support this practice. It’s likely more of a tradition or old wives’ tale than anything else.
People put stones on the watermelons to avoid sunlight. The stone is a good conductor of heat and absorbs heat from watermelons during the night and prevents watermelons from cracking.
The stones help prevent birds from eating the watermelons. When birds land on the melons with stones on top, they will not be able to stand firmly to eat. Thus, the birds will be scared and fly away.
Farmers mark the ripe melons. Watermelons usually take up to a month to ripen after fruiting.