Luffa Sponges are grown from seed on a vine that looks like a cucumber. Seeds are planted after the threat of frost is past, and after a very long growing season, the mature Luffas turn brown and become very light. Once harvested, they are soaked in water until the skins slip off. Then they are rinsed with clean water and set out to dry. Once dry they are ready to use, just run warm water over them briefly and enjoy.