Why are my watermelon vines growing but the fruit isn’t?

Start with flowers and pollination. Watermelons have male and female flowers, and a tiny melon behind a female flower can wither if it doesn’t get pollinated. Bees and other pollinators need access, so avoid spraying insecticides while the flowers are open. Plenty of direct sun helps the plant flower and set fruit, too.

If flowers are present but fruit still fail, heat stress can be part of it. Keep the root zone watered and try to direct the vine away from hot concrete or other surfaces that reflect or radiate extra heat.

For small melons that crack or develop a brown patch, check for swings in watering and very hot conditions around fruit set. Keep moisture fairly steady rather than letting the bed get very dry and then soaking it. A crack alone doesn’t identify the cause, so look at the plant and the fruit together before adding fertilizer or supplements.

Raised beds can work, but the vines need room to spread and the fruit shouldn’t be trapped against a hot, rough edge. Give the plant space, and if a developing melon rests on soil or a hard surface, set it on a clean, dry support so it isn’t sitting in dampness. A trellis can save space, but heavier fruit need solid support.