Winter squash

Cucurbita

Butternut, acorn and onion squash are all winter squashes. They have hard skins and keep through winter. Trailing kinds spread a long way. Smaller ones can be trained up a sturdy support. Leave the fruit on the plant until it is fully ripe, because an unripe squash won't keep.

Looking after it

Water: Winter squash needs a lot of water. Water generously while the fruit swells, onto the ground and not over the leaves. A mulch around the plants holds moisture in the soil. Feeding: It needs rich soil. Dig plenty of compost or well-rotted manure into the planting spot. On poor soil, give a liquid feed high in potassium every 10 to 14 days once the fruit swells.

Harvest and keeping

A squash is ready when the skin is hard and dull, a fingernail doesn't dent it and the stalk is firm. Cut it before the first frost, with a long piece of stalk. Then leave it in the sun for about 10 days so the skin hardens. Store the hardened squashes somewhere dry and airy at 10 to 15 °C. Depending on the kind, they keep one to six months. Check them often and use any that go soft.

What can go wrong

Powdery mildew. White powder appears on the leaves, worse when the plants go dry. Water steadily and give plants room so air can move.
Slugs and snails. They eat young plants and flowers. Protect the plants after you plant them out, especially in damp weather.
Small fruits shrivel. In cool weather few insects visit the flowers, so the small fruits shrivel or rot. To pollinate by hand, brush pollen from a male flower into a female flower. You can tell the female by the small fruit behind it.

Growing facts: RHS, UC ANR and seed-company sowing guides. Squash care: RHS. Ripeness and keeping: University of Minnesota extension and RHS. How many to grow: Kansas State and Virginia Tech extension. pH: Virginia Tech extension.