Luffa is a genus of tropical and subtropical vines in the cucumber (Cucurbitaceae) family. In everyday non-technical usage, the luffa, also spelled loofah, usually means the fruit of the two species L. aegyptiaca and L. acutangula. The fruit of these species is cultivated and eaten as a vegetable. The fruit must be harvested at a young stage of development to be edible. The vegetable is popular in China and Vietnam. When the fruit is fully ripened, it is very fibrous. The fully developed fruit is the source of the loofah scrubbing sponge which is used in bathrooms and kitchens. Luffa are not frost-hardy, and require 150 to 200 warm days to mature.