Plant scientists are reinventing the watermelon, that most traditional of all summertime fruits. New “mini” varieties fit easily into refrigerators. Seedless melons are easier to eat. Reduced-sugar hybrids a year or so from production will appeal to dieters and diabetics.

And watermelons ripen during the sweltering heat of mid-summer, perfect timing for a sweet and hydrating fruit made up of 92 percent water.

“You think of it (when you’re) hosting parties,” says Leslie Coleman, director of communications for the National Watermelon Promotion Board in Orlando, Fla. “You go into the grocery store and see watermelons splashed all over the place. It conjures up good memories.”

There are believed to be more than 100 watermelon varieties at present, ranging from the familiar “Charleston,” which matures at around 25 pounds, to the icebox-sized “Yellow Baby,” a yellow-fleshed variety. Seedless melons like the “Triple Sweet” are popular but require more management in the garden, particularly with pollination.

Watermelons are frost-fragile plants, so plant them in full sun and well after the soil warms. Depending upon size and variety, melons mature in 70 to 85 days. Mulching with black plastic sheets inhibits weeds, holds moisture and speeds growth.

Watermelons grow large, 5 to 100-plus pounds, so give them plenty of room – as much as 6 feet between plants.

Harvesting can be tricky. Thumping a melon with your knuckles to elicit a soft hollow thud is a popular test for ripeness, but more certain is rolling the melon over for a look at the “ground spot.” If the patch where the melon rested on the ground is light green or white, then the melon isn’t ripe. Wait until it turns a dull yellow or creamy before cutting it from the vine.

Melons should be stored on the warm side when brought into the home.

Compared to most fruits, watermelons need a more tropical climate – a thermometer reading of 55 degrees is ideal, according to the National Watermelon Promotion Board.