Luffas have magical appeal to kids, so growing luffa can be an exciting family or classroom project for your summer garden. Also known as dishcloth gourds or vegetable sponges, luffa are actually Chinese vegetables in the cucumber family that are edible and useful. The most common luffa grown for sponges is smooth luffa (L. aegyptiaca).
The fast-growing vines will need a sturdy trellis to keep the luffas off the ground so they don’t rot before they are ready to harvest. Start luffas from seeds in warm soil in late spring. Seeds are readily available through most garden catalogs.
For more information on growing Chinese vegetables see, HGIC 1306, Chinese Vegetables.
The warm-season annual vines will soon be covered by pale-yellow flowers that develop into small squash-like fruit within a few days. When harvested young, they are tender enough to be eaten raw or cooked, as you would squash or eggplant. The fruits grow at a rate of an inch to an inch-and-a-half per day making it a challenge to find and harvest the fruit while they are still tender enough to eat.
When the fruits are allowed to grow larger, they develop tough inner fibers that can be used as shower or kitchen sponges, transformed into luffa soaps, and even used as chew toys for pets such as rabbits and hamsters!
Luffa sponges are ready to harvest when the skin feels loose and brittle around the hardened fibers inside. To process the sponges, peel the skin off, shake the seeds loose (save some for next year) and dip in a bucket of 10 parts water to 1-part bleach for about an hour to remove any stains and allow to dry.