Fresh leeks are not green onions. Learn everything you need to know about growing leeks to add a mild onion flavor to your favorite dishes. Better Homes & Gardens Leeks are a popular and easy-to-grow vegetable often used to add a mild onion flavor to soups, casseroles, salads, and stir-fries, but they can also be eaten raw. While a leek is part of the onion family, it differs from an onion....