Available year-round, spinach thrives in temperate regions from April through the summer months. There are three types of spinach: Savoy (crunchy and crinkly), semi-Savoy (slightly less crinkly and crunchy), and flat-leaf (smooth and tender). The flat-leaf type, grown in California and the most popular spinach on the West Coast, is sold in bundles, while the two Savoys tend to be sold loose and by the pound. Search for dark green leaves with firm stalks, and avoid any yellowish-brown, limp leaves. All three types of spinach are packed with fiber and nutrients such as beta-carotene, protein, and vitamins B, C, and E.