I have been getting a lot of questions lately on how to handle a luffa or loofah gourd to get a usable sponge.
Luffa or sponge gourds should be harvested when the outer shell is dry. When you can hear the seeds begin to rattle around inside, remove the stem end and shake out the seeds from the center cavity. Save some seeds to replant next season.
Then you can begin to remove the outer rind. You can peel the skin, or soak the gourds in warm water until the outer skin softens to the point where it can be easily removed, or use running water to help soften the outer skin. Once the sponge is removed, soak it in one part bleach to nine parts water to obtain the creamy white appearance.
Rinse it in clear water and dry before using.
The luffa gourds bloom need a long growing period to produce sponges.
They bloom during the day with yellow flowers. To help produce large, straight fruits, it is best to grow them on a trellis or fence. At maturity the fruits turn brown. The outer shell is removed to expose a tough, fibrous interior that is used as a sponge. These gourds can be eaten when they are immature.
If they are harvested when quite small and green they are alled vining or Chinese okra, and can be used like okra.