Every summer, the same rumors resurface: watermelons are injected with sweetener to taste better, and seedless ones are genetically modified. None of it is true. Here's what the science actually says — and how to pick and store the perfect melon.
The Sweeter-Every-Year Myth
Watermelons do taste sweeter than they used to — but the reason is better breeding and farming, not additives. Sugar content in modern varieties now reaches 13 to 15 percent, far higher than older ones. As for injecting sweetener: even injecting plain water would cause the fruit to rot within days, making it commercially worthless.
Seedless Does Not Mean GMO
Seedless watermelons are the product of chromosome engineering, not genetic modification. Standard watermelons have two sets of chromosomes (diploid). Scientists use a plant-derived chemical called colchicine to create plants with four chromosome sets (tetraploid), which are then crossed back with normal diploid plants. The resulting hybrid has three chromosome sets and cannot produce viable seeds — hence, seedless. No foreign genes are introduced at any stage.
Other Myths, Dismissed
Claims that eating watermelon alongside peaches is dangerous, or that leftover watermelon is unsafe, have no scientific basis. The concept of "food incompatibility" is not supported by evidence. For leftovers, the guidance is simple: refrigerate promptly, wash the rind and knife before cutting, and don't worry about the rest.
How to Pick a Good One
Tap it. A ripe watermelon has softer flesh due to natural fiber breakdown, producing a low-frequency, drum-like sound with a slight vibration. Overripe melons sound dull; underripe ones produce a higher-pitched, crisper tap.
Look at the stripes. Clear, dark stripes with wide spacing between them indicate good quality. A fresh green stem means a recent harvest. A curved stem suggests ripeness; a straight one may mean the fruit is underripe.
Check the ends. A slightly sunken belly button and stem end are typical signs of a ripe melon. Ripe melons also lose their surface fuzz and feel smooth. If the rind feels soft or sunken anywhere, the inside may already be spoiling — skip it.
How to Store It Safely
For whole watermelons, rinse with cold water, wipe the outside clean, and pat dry before refrigerating.
When buying pre-cut or packaged watermelon, choose only pieces that are refrigerated or surrounded by ice.
Always cut watermelon with a clean knife.
Don't leave cut watermelon at room temperature for more than three hours.
Wrap cut pieces tightly in plastic or store in an airtight container in the fridge, and eat within 24 hours — the sooner, the better.
Store watermelon away from raw meat, poultry, and seafood.