It's highly ornamental, bees love it, the fruit is edible and delicious, mature fruits have many household uses, and the plant is easy to grow. What's not to love?
When I show people luffa fruits, nine times out of ten they'll be surprised that luffas come from a plant. Most people seem to think they come from a sea creature. Indeed, luffas do grow on plants, just like their close cousins the cucumbers. In fact, the plant very closely resembles cucumbers, except luffa vines seem to grow ten times as long and the blooms are a hundred times as large.
If you didn't know, luffas have a variety of uses around the house. Plenty of people use them in the bath as a scrubber, and they also make great scrubbers for pots and pans. I've heard of people using them to wash their cars, lawnmowers and tractors. They also have a really nice weave to their fibers which makes them quite useful in filtering systems. Using them to filter pond and aquaponics water is a nice all-natural solution with no waste. When the luffa fibers are clogged with pond gunk, just throw the whole thing into the worm bin and then stuff a new luffa into the filter housing. Pretty cool. In the past, luffa fibers have been used in various insulating applications, including military helmets. I've read claims about medicinal uses for luffa, but there seems to be a lot of confusion around that subject, so you'll have to just do your own research on that one if that interests you.
The seeds are similar to squash seeds, and jet black in color. While I've had plenty of success sowing the seed directly in the ground, it's more foolproof to start them first in six-packs and then transplant them to the garden after they've gotten a good start. They require a good four months of frost-free weather to grow and ripen fruit, so the earlier you get started, the better. Of course, down here in East Texas we have more than enough growing season, so we just start them whenever we feel like it. Once you've grown them in a certain spot, if you leave some fruit to drop their seeds, you'll likely see them reseed themselves year after year. This is how we continue to grow our luffas - we just let a few reseeded plants live.
As I mentioned earlier, it's a vine, and an extremely long one at that. In fact, it's the longest vine I grow, easily reaching lengths of 25' or more. If you give it a trellis, it'll climb to the top of it, then lean down and grow back to the ground. Once it hits the ground, it will turn around and climb back up again. It'll do this again and again until your trellis is a mesh of luffa vines. It is an amazing sight to see, and beautiful, too, for once the blooms open you'll realize the other reason I love it: the flowers.
Luffa blooms are bright yellow and about four to five inches across. Abundant male flowers open pretty early in the season, followed some weeks later by periodic female blooms. The honey and bumble bees will spend much time visiting these, gathering valuable pollen. I have an eight-foot-tall tee pee, made from cedar logs leaning against each other, that when covered with luffas shows dozens of blooms at a time and it is a spectacular thing to see. It continues to bloom all summer long.
Tee pees, trellises, fences, and water downspouts all make perfectly fine luffa supports. We have one gigantic tee pee that we made from cedar logs that's about 25 feet tall, and the luffas climb to the very top of it and continue down the other side! As with other vegetables, it performs its best in full sun with fairly good soil. In our experience, though, soil that is too rich in nitrogen will prevent it from making fruit. It'll just get big with some blooms but will never actually produce the luffa gourds. We always seem to get the best results by growing it in the poorest soil we can find.
Once the female flowers start appearing, the fruits are quick to follow. They look just like smooth cucumbers, and they can be eaten up until they get to about 6 inches long. There are numerous ways to eat these, but my preferred way is to harvest them at 6 inches, then slice them into fairly thin slices. Melt a good bit of butter in a sauce pan, and start tossing around the luffa slices. While cooking, sprinkle a bit of freshly cracked pepper with some quality grey salt. It makes an outstanding side dish for any meal.
Those fruits that you don't eat will continue to get bigger and bigger until finally they reach their full size: about 18 inches. The green skin will turn brown and the fruit will dry out completely. At that point, if you shake the fruit you will be able to hear the seeds rattling around inside it. You can leave it in this state as long as you want, but eventually you'll cut it from the vine and prepare it for processing.
On the bloom end there is a little cap that you can conveniently remove and the seeds will then pour right out. Harvesting the seed couldn't be more convenient! Save those seeds for next year. Once that's done, loosen the skin by dunking the luffa into a bucket of clean water for about 15 minutes. Once it's soaked, the skin peels off as easily as a banana peel. At that point you will have a brownish luffa exactly like you'd buy at the store. If you want it to be lighter in color, you can soak it in a mild bleach solution. Dry them in the sun and you're done, and they can be stored indoors indefinitely.
So, where does one get seeds for luffas? A few of the vegetable seed catalogs offer them for sale, and my favorite by far is Victory Seed Company. View their offerings at www.victoryseeds.com and while you're there, check out their nice selection of other interesting heirloom vegetables. They have been preserving heirloom vegetables for a very long time and have a well-deserved reputation for their good work.
Want to see more? We have a good number of pictures of luffas and more info in our plant database at Sponge Luffa (Luffa aegyptiaca)