Luffa

Luffa cylindrica, L. acutangula

In Asia, luffa is a trellis crop, grown mainly for young fruits, which are harvested as vegetables. When the fruit is fully matured, it is very fibrous. People use the ripened fruits to make luffa scrubbing sponges which are used in the kitchen and bathroom. This is why luffa is also referred to as sponge gourd.
Other names: Luffah, loofah, loofa, Chinese okra, Chinese vining okra, Dishcloth Gourd, Sponge Gourd, Vegetable Gourd, Cee Gwa, Running Okra, California Okra,  Strainer Vine, Tsee Gwa, Si Gua, Ssu-Kuo, Shui Gwa, Man Gua, Hechima, Muop Huong, Belustra, Loang, Oyong, Petola manis, Silk Melon, Sing-kwa, Sheng Gua, torai, turai, gilki, ghiura, 丝瓜, 胜瓜.

There are two types of luffa: smooth luffa and ridged luffa.
Smooth luffa (Luffa cylindrica, synonyms L. aegyptica, L. aegyptiaca): The fruit is long or short cylindrical-shaped with smooth skin. 
Ridged luffa (Luffa acutangula) is also called angled luffa, ribbed luffa, Chinese okra. The fruit is ridged.

Seed pre-treatment and germination are recommended: pre-soak the seeds in hot water at 45°C~ 55°C for 20 minutes, then soak them in warm water at 30°C for 24 hours. Optimum germination temperature: 30-32°C.