Do your young zucchini or pumpkins suddenly shrivel up and die without warning, even though the plant looks perfectly healthy? If so, not to worry. Your plant is fine! The problem is with pollination. Winter and summer squash, pumpkins, melons, and cucumbers all belong to the Cucurbit family. Cucurbits are monoecious, which means male and female flowers develop on the same plant.
It is easy to tell the difference between the two types of flowers: female flowers have a little baby squash (or cucumber or melon) right behind the flower. Males don’t. Female flowers also have a sticky, crown-shaped organ called a stigma at the center of their blossom. Male flowers have anthers, which look like a popsicle dipped in pollen. In order for the fruit to develop, pollen from the male flowers needs to be deposited on the stigma of the female flower. Bees usually do this job, but if your fruit are rotting away before they develop, that is a clear signal that pollinators are not finding your cucurbit plants.
Luckily, it is easy to step in and pollinate the plants by hand. Cucurbit flowers open for one day only and they usually shrivel in the heat of the afternoon, so it is best to hand pollinate in the morning. Simply pick off an open male flower (again, they have straight stems and no fruit behind the blossom). Peel off its petals to reveal the pollen-covered anthers. Rub pollen from the anthers all over the center of an open female flower. That’s it! You’ll know the pollination process worked when the fruit begins to grow.
Willi Galloway is the author of Grow Cook Eat: A Food Lover’s Guide to Vegetable Gardening, and she writes about organic vegetable gardening and seasonal cooking on her blog, DigginFood.