From garden plant to soapy scrubber. With a little effort, a homegrown luffa gourd can become a handy bath accessory that "lasts for years."
Natural sponges come from the sea, right? That’s true for most absorbent sponges, but one popular scrub sponge can be grown in your own backyard. Luffa (sometimes spelled loofah) sponge gourds are easy to grow in South Carolina. Closely related to cucumber and winter squash, they thrive in the same conditions.
To perform best, luffa gourds will need a site with full sun, rich, well draining soil, ample moisture and a sturdy trellis to climb. Luffa plants require a long season to produce usable gourds. They are best grown from seeds planted indoors four to six weeks before the average last-frost date in your area.
Luffa seeds are slow to germinate, but soaking them in warm water for 24 hours will hasten germination. Plant two seeds a half-inch deep in peat pots, and, if both seeds germinate, remove one to give the other room to grow. As your young plants grow, prepare your garden soil based on soil-test results. After the danger of frost is past and the soil is warm, plant the transplants outside with three to four feet between plants in a row.
Vigorous luffa vines will require plenty of water and fertilizer, so water deeply once or twice per week if rainfall is inadequate. As the plants begin to run, train the vines up a trellis or other sturdy structure. Keeping the fruits off the ground will reduce fruit rot and lead to straighter, more attractive sponges. When the first blooms appear, side-dress each plant with three tablespoons of calcium nitrate. One or two more side-dressings may be needed, depending on your soil type or if heavy rains occur.
Luffa sponge gourds are generally pest-free. Cucumber beetles and spider mites may occasionally become a problem. An insecticide containing carbaryl that is labeled for vegetables can be used to manage cucumber beetles. Insecticidal soap is an effective treatment for spider mites.
If all goes well, you can harvest usable sponges in early fall, about 130 days after transplanting. A healthy plant will produce 10 to 20 gourds that may be up to 18 inches long and weigh as much as three pounds each when green. As the gourds mature, their interior fibers begin to harden, and the green skin will start to yellow and then turn brown. Harvest the fruit once they are brown, lighter in weight and mostly dry. At this point you can process the gourds into their finished product, or you can allow them to dry completely and store indefinitely in a dry, ventilated location.
The “sponge” part of the gourd is the fibrous interior of the fruit. To make it usable, you will need to remove the skin, seeds and adhering pulp. Start by removing the bloom end of the fruit—it will pop off easily—and shake the seeds out. If there was no cross-pollination from other crops like squash, pumpkin or other gourds, you can save the seeds to plant next year or share with friends. Next, soak the gourd in warm water for five to 20 minutes to loosen the skin, and then strip it from the fibers. It should come off easily.
You could leave the sponge its natural color and it would be fine for scrubbing, but most people prefer to improve its appearance by soaking in a 10 percent chlorine bleach solution for 15 minutes or until it reaches the desired color. Finally, rinse the bleach from the sponge with clean water and air dry. Once the sponges are dry, they can be cut into desired shapes and sizes and put to use as scrubbers in the bathroom, the kitchen or the garden shed.
These natural sponges are extremely durable and will last for years. I use one in the shower every day. If they become dirty, simply bleach again or throw them in the washing machine.
S. CORY TANNER is an area horticulture agent and Master Gardener coordinator for Clemson Extension based in Greenville County. Contact him at shannt@clemson.edu.