Start by examining the entire rind. Choose a watermelon that feels firm and looks intact, without deep bruises, cracks, cuts, or noticeably soft areas. Superficial scratches and natural markings aren’t necessarily a problem. You might also notice brown, web-like marks sometimes called “sugar spots.” Despite the popular nickname, these markings don’t guarantee that the watermelon inside will be unusually sweet, so don’t rely on them alone.

Next, compare the weight. Pick up several watermelons of approximately the same size and notice which one feels heavier. A melon that feels heavy for its size generally contains plenty of water, making this a useful clue when looking for juicy fruit. If a stem is still attached, inspect that too. A dry, brownish stem can be consistent with maturity, whereas a very green one may indicate earlier harvesting. However, stem appearance can also be affected by handling, so treat it as another clue rather than a guarantee.

What about the famous tapping test? Many shoppers knock on watermelons and listen for a deep or hollow sound, but tapping isn’t a reliable test of sweetness. Shape isn’t a guarantee either. Instead of searching for one magical trick, combine several clues: a creamy yellow field spot, firm undamaged rind, reassuring weight for its size, and an overall healthy appearance. Together, these observations can improve your chances of choosing a good watermelon, even though none can promise perfect sweetness.

Finally, remember food safety. Before cutting your watermelon, wash the rind thoroughly under running water and dry it. Dirt and bacteria on the outside can potentially be transferred to the flesh by your knife. Refrigerate cut watermelon promptly and keep it chilled.

So next time you’re choosing a watermelon, turn it over, inspect it carefully, compare its weight, and use several clues instead of trusting just one popular trick.