Winter squash is a summer-growing annual fruit, representing several squash species within the genus Cucurbita. It differs from summer squash in that it is harvested and eaten in the mature fruit stage, when the seeds within have matured fully and the skin has hardened into a tough rind. At this stage, most varieties of this fruit can be stored for use during the winter.
Winter squash is a low-calorie, good source of complex vegetable carbohydrates and dietary fiber. It is an excellent source of vitamin A, a great source of vitamin C, potassium, dietary fiber and manganese, and a good source of folate, omega 3 fatty acids, vitamin B1 (thiamin), copper, tryptophan, vitamin B6 (pyridoxine), vitamin B3 (niacin) and vitamin B5 (pantothenic acid).