Allow gourds to ripen on the vine, hang to dry, remove the skin, and voila--you have your own luffa sponges. Trellising recommended for straight fruits.
3" peat pots
How to Produce a Luffa Sponge -From Fedco Seed Co
When luffas are ripe their skins turn brown and dry and stems turn yellow. Check your plants frequently and harvest only ripe gourds. Full-sized fruit that are still green produce soft, fine-textured sponges that don’t last. After the first killing frost remove any nearly ripe gourds to a warm well-ventilated place to allow them to dry. Gourds left wet for long will readily discolor.
If the luffa has just ripened, gently squeeze and pop its skin. Break the blossom end cap and pull the vascular bundle (that’s the sponge!) up the side of the gourd like a zipper. The sponge will pop out, wet and white. Quickly rinse it in water to prevent oxidation.
If gourds are too dry to pop the sponge out, ret them (thoroughly soak in water) for several days until the skin sloughs off leaving only the spongy fiber. After retting, shape and dry the sponge. Remove seeds either before or after retting. We found it easy to do before retting: cut open the larger end of the gourd and either shake or rinse out the seeds. If you wish to whiten the sponges, bleach by soaking either in a 10% bleach solution or in hydrogen peroxide. Rinse luffas thoroughly in clean water and dry before use.