Spinach (Spinacia oleracea) is a cool-season annual leafy green in the Amaranthaceae family. It is grown for its tender, dark green leaves and is valued for its high nutrient density. Spinach is native to Central and Western Asia.
Spinach was first cultivated in Persia (modern Iran) over 2,000 years ago. It spread to China in the 7th century and to Europe in the 11th century through Arab traders. Spinach became a popular garden vegetable in Europe by the 16th century and was brought to North America by colonists.
Spinach is consumed fresh in salads, cooked as a side dish, and used in soups, quiches, and smoothies. It is an excellent source of iron, calcium, vitamins A and K, and folate.
Spinach is harvested by cutting the outer leaves 2 to 5 centimeters (1 to 2 inches) above the crown, allowing the center to continue growing. Bolting (premature flowering) occurs in long days and warm temperatures. Spinach is stored in the refrigerator for 5 to 10 days. For long-term storage, it is blanched and frozen.
Spinach grows best in cool temperatures between 4 and 20 degrees Celsius (40 to 68 degrees Fahrenheit). It bolts quickly in warm weather and long days. Succession planting in spring and autumn extends the harvest season. Spinach requires consistent moisture and fertile soil.