Squashes can be sown between March and May and harvest between July and October. They like plenty of sun and space but some varieties do just as well in containers. If sowing early start them off indoors before planting out after the last frost. Direct sow from late May or early June. Sow between two-to-three seeds at each growing position and thin seedlings out. It's a good idea to dig well-rotted manure into the soil before planting.