Q: How do you harvest luffa gourds?
A: In autumn, mature gourds will begin to turn brown and brittle. Check plants frequently and remove any dried gourds. These will feel light and dry, and rattle with loose seeds when shaken. After the first killing frost, remaining gourds can be brought inside to dry.
Cut off the ends of the gourds and beat the gourds gently together to shake out the seeds. Save those from the most vigorous vine.
Soak the dry, brown gourds in warm water, until the skin is easy to peel off. Soak the sponges in a 1:10 bleach:water solution for a few minutes to lighten the color. Depending on your intended use, cut the sponge along its length or across its width and allow to dry completely.