Lettuce is a hardy, fast-growing annual vegetable with either loose or compact leaves. Leaf color ranges from light green through reddish brown. The lettuce most commonly found in supermarkets (iceberg, or crisphead, lettuce) is the most difficult to grow. Butterhead lettuces, which have loose heads and delicate crunchy leaves, are easier to grow. Cos, or romaine, lettuce forms a loose, long head and is between a butterhead and leaf lettuce in flavor. Leaf lettuce is delightfully easy to grow, grows fast, and provides bulk and color to salads.
It's hard to imagine a salad or a sandwich without lettuce. With so many diverse varieties to choose from, there's a lettuce for every taste. Lettuce is also an ingredient in many delicious vegetable recipes.
Depending on the variety, lettuce is a good source of vitamin A, vitamin K and potassium, with higher concentrations of vitamin A found in darker green lettuces.