Luffa is a genus of vines from the tropics and sub-tropics.
L.cylindrica, below, is most likely to be cultivated, it typically grows at least 10 feet. This plant has yellow flower which appear in the summer and club-shaped fruit which are 1 foot long.
Seeds will grow in spring, plant them in large pots in your greenhouse and train the growths towards the apex of the greenhouse. They need plenty of water during the growing season and syringing is essential.