The thin-skinned summer squash have few calories and many uses in the kitchen. The thick-skinned winter squash have darker flesh and are a prime source of beta-carotene and minerals. Winter squash grown in summer develop a firm skin that protects the squash for winter storage and eating. Field-cure for 10 days in the sun, or cure indoors in a warm room for 4-5 days. To prevent mould, sponge the skins with clean water before storage.