Luffa gourds (also spelled “loofa”), are sometimes called “dishcloth gourds” or “vegetable sponges.” The name comes from luff, the Arabic word for this plant. Luffa gourds are grown primarily for their fibrous tissue skeleton, which is commonly used as a bath or sauna sponge, but young fruits, less than 7 inches long, can be cooked and eaten as squash or substituted for cucumber in salads.
Leaves and vines resemble cucumber foliage, a clue that luffas are related to cucumbers, squash and other gourds. Fruits look a bit like overgrown zucchini or cucumbers, reaching a length of 2 feet. They remain green until they’re thoroughly ripe.
Luffas are extremely vigorous plant; vines reach lengths of 15 feet or more! They make an excellent summer screen plant, as they will thoroughly cover every inch of fencing available to them. The plants flower and set fruit all season.
Luffa gourds require a season longer than Minnesota’s to ripen fully, but they will reach full size. (The author so far has been unable to produce fully-ripened fruit in the Twin Cities/USDA zone 4, between May 10 and the first frost.)
If you wish to try growing luffa gourds, start seeds indoors several weeks before the desired transplant date. Seeds can take up to 2 weeks to sprout. Pre-soaking in warm water for 48 hours will speed germination. Set transplants out as soon as the soil has warmed, probably the second half of May, then protect the plants from frost both spring and fall. Plant one to three plants in a hill, with hills at least 6 feet apart.
Grow the luffas on a sturdy, tall trellis or a fence at least 5-6 feet high. Without a trellis, vines will quickly overrun the garden. Mulch mid-summer with compost or grass clippings, to help conserve moisture and control weeds.
When the gourds are ripe, their skins will dry and the stems will turn yellow. Full-size fruits that are still green produce soft, fine-textured sponges that don’t last. Green fruit is also very sensitive to frost – if no yellow or dry fruit have been produced by frost you will need to provide protection to give the fruit more time to ripen.
Here are two techniques you can use to make a sponge, if you get some gourds that ripen:
Let the ripe gourd dry for 2 weeks. When its skin has hardened and turned brown, open the larger end of the squash and shake out the seeds. Soak the gourd overnight in water, then peel off the skin. Let the gourd dry in the sun.
Another method is to soak the ripe gourds in luke warm water for several days until their skin comes off easily. Rinse out the interior of each gourd with water to remove seeds and pulp. Set cleaned gourds in the sun for a week or so to dry.
Edited by Jill MacKenzie, Former Extension Specialist, Horticulture, University of Minnesota Extension 9-07.
Reviewed by Cindy Tong, Extension Post-Harvest Horticulturist, Univ. of Minn. Extension, 1-08 and Vince Fritz, Extension Horticulturist – Vegetables, Univ. of Minn. Extension 1-08.
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