How to Grow and Care for Luffa

Luffa (Luffa aegyptiaca), also frequently spelled "loofah," is a fast-growing, tendrilled vine with large yellow blooms producing gourds and attracting bees and butterflies. Luffa is native to Asia and grows best in hot weather, acidic soil, and at least six hours of sunlight. The unique luffa gourd fruits are eaten or dried for use as natural sponges. They take about 90 to 120 days to grow and up to 200 days until it is ready to be harvested for sponges.

Luffa Care

Here are the main care requirements for growing luffa plants:

• Needs full sun, hot temperatures, and time to grow sufficiently.
• Provide a trellis or posts with wires to allow vining and air circulation.
• Keep fruits off the ground to prevent rot, discoloration, and uneven, curved growth.
• Requires acidic soil between 6.0 to 6.5 pH range.
• Keep soil moist; needs at least 1 inch of water per week.
• Fertilize with nitrogen two to three times during the growing season.
  

Light

Luffa needs at least six or more hours of full sun—the more the better.

Soil

Luffa can grow in any soil type (it prefers a pH range of 6.0 to 6.5) but requires good drainage. Ensure you can offer well-draining soil to prevent your luffa plant from over-saturating.

Water

Keep the soil moist but not wet until the seedlings are established. After that, without sufficient rain, water the base of the plants about 1 inch per week. Do not water the vines, which can spread disease.

Temperature and Humidity

Luffa needs warm to hot weather. In cool weather, its growth will slow down.

Fertilizer

Add organic matter to the soil before planting, and add nitrogen-rich fertilizer two to three times during the growing season. For the amount to use, follow the product label instructions.

Types of Luffa

Luffa aegyptiaca, also called smooth luffa or sponge gourd, is the variety most widely available from seed companies. Common cultivars include: 'Smooth Boy', 'Smooth Beauty', and 'South Winner.'

There are two other luffa species:

• Angled luffa (Luffa acutangula): Also called Chinese okra, dishcloth gourd, or ribbed loofah, its immature fruits are popular in Asian cuisine. Common cultivars include: 'Lucky Boy,' 'Hybrid Green Glory,' 'Summer Long,' and 'Hybrid Asian Pride.'
• Ball luffa (Luffa operculata): Also used as a fibrous scrubbing sponge similar to Luffa aegyptiaca
  

Pruning

Trim young plants with sterilized pruners. To encourage vigorous branching, cut four stems back to the main stem. Luffa vines can get up to 30 feet long, with 10-inch palm-shaped leaves.

Grow them on a trellis like those used for cucumbers and pole beans, as long as the frame is strong enough to support the weight of the mature luffa gourds. Or use 4-inch by 4-inch posts, set 10 feet apart, with heavy gauge horizontal wires at even intervals to the top. To train the vines, add a string in a V-pattern so the tendrils of the vines have something to grab onto.

Luffa that is grown on the ground tends to be curved. Keeping the vines and fruit dry and off the ground reduces the risk of disease and rotting in humid or wet weather.

Once the plant develops fruits, about two months before your first expected frost date, pinch away all the flowers and any small luffa on the vine. Pinching the most miniature fruits and flowers will direct the plant to put all its energy into growing the existing luffas on the vine into larger fruits.

Harvesting Luffa

Luffa is in the cucumber family. You can harvest luffa when it is still young and tender for eating raw or cooked. The fruit grows fast, about an inch-and-a-half per day. Expect about four to six fruits per plant. It's easiest to grow luffa for sponges and let them grow about two feet long. Here's how to harvest luffa:

1. Once the fruit has reached maturity, allow it to remain on the vine for several weeks to give it time to develop its tough inner fibers. Give it 150 to 200 warm, frost-free days from seed to harvest.
2. Dry it on the vine before harvesting it. Cut the fruit from the vine with one to two inches of the stem attached; they should be tan and lightweight. Their skin should be thoroughly dried to a hard shell. When you shake a luffa, you should hear the seeds rattle inside, which indicates that the inside fibers have also dried and hardened.
3. To make sponges, immerse the luffa in warm water for about 20 minutes or until the skin can be easily removed. Remove the seeds by shaking them loose, and remove any pulp.
4. Once the luffa is gutted, soak it with a 10 percent bleach solution for one hour to kill bacteria. If you prefer not to use bleach, rinse it well under fresh water, shake it to remove excess water, and microwave it for one to three minutes until it's steaming hot. Allow it to dry in a warm, well-ventilated place before storing.

Propagating Luffa

Luffa is an annual plant and is only propagated by seed. However, crop and fruit production is only possible by pollinating the plant's flowers during the growing season.

Pollination of female flowers occurs primarily through bees. If you notice a lack of bees, consider hand pollination when the plants are flush with flowers. Male and female flowers look similar, but male flowers grow on a long stalk and are usually the first to appear. The flower blooms for one day and then fall off. The female flower grows on a short stalk (peduncle) but has an ovary in the shape of the fruit.

Here's how to hand-pollinate:

1. Use a small paintbrush or cotton swab to move pollen from a male flower to a female flower or gently rub the male flower's yellow hair-like structures against the female flower's middle parts.
2. Repeat for two to three days.
3. Fruits should start to form shortly after pollination.

If there is a lack of male or female flowers, it could be the nutrient levels in the soil need adjustment. Soil high in nitrogen yields more male flowers; soil high in phosphorous produces more female flowers. Adjust according to your plant's output of male vs. female flowers.

How to Grow Luffa from Seed

Because of its long growing season and warm temperature requirements, luffa is best seeded directly in your garden. Starting the seeds indoors requires four to six weeks in a greenhouse-like setting at about 65 to 70 degrees F with full sunlight.

1. In late spring, when the soil has reached at least 70 degrees F, sow seeds in well-drained, tilled soil, three to four seeds per plant, and leave about six feet between the plants. Do not plant luffa in a location where you grew other members of the cucumber family (Cucurbitaceae) the year before.
2. Cover the seeds with 1/2 to 3/4 inches of fine soil, lightly tamp them, and moisten them evenly.
3. Ideally, seedlings emerge in seven to 14 days, but germination can be slower depending on the seed quality and soil temperature.
4. Thin to one seedling, keeping the most vigorous plant, when they are one to two inches high. If you don't start with a trellis but plan to drive posts or a cage system, keep the post away from the plant's tender root system.

Potting and Repotting Luffa

You can start luffa as seedlings indoors in pots. They will eventually need to be transplanted outdoors and require a trellis or other support for growing their large, pendulous fruits. Luffa plants are cold-sensitive, so harden them appropriately and only bring them outdoors when the temperatures are consistently above 50 degrees Fahrenheit.

Luffa plants can be grown in large containers in a container garden but provide a trellis or support structure for the plant to vine upwards. Also, ensure the container has ample drainage holes since this plant does not like wet feet (consistently wet roots) or soggy soil.

Overwintering

Luffa are annual plants, living their entire lifespan in one growing season. These plants do not overwinter since cold temperatures kill the vines. If frost threatens before the fruits have fully matured, cover the plants lightly to shield them from the frost.

Common Pests & Diseases

Downy mildew, powdery mildew, alternaria leaf blight, and angular leaf spot have been observed on luffa, but thankfully luffa is not frequently affected.

Rarely, invading pests can include cucumber beetles and spider mites. Practicing crop rotation and avoiding overhead irrigation helps reduce the spread of disease.

How to Get Luffa to Bloom

Bloom Months

Luffa usually blooms in June, or after about 90 days in the ground.

How Long Does Luffa Bloom?

Luffa flowers are short-lived, blooming for about one day until the flowers fall off.

What Do Luffa Flowers Look and Smell Like?

Luffa flowers are yellow, appearing very similar to squash flowers. Male flowers usually cluster, while female flowers are singular and look like small fruiting bodies before blooming. They are mildly fragrant and most often bloom at night.

How to Encourage More Blooms?

Nitrogen and phosphorus additives to fertilizer are directly related to producing male and female flowers. Add more phosphorus to the fertilizer mix to encourage more female flowers to fruit.

Caring for Luffa After It Blooms

After the bloom period and fruits have begun to form, pinch away the remaining flowers to turn the plant's energy away from flower production and toward larger fruit growth.

Deadheading Luffa Flowers

Deadhead flowers that don't naturally fall away. If your luffa plant has already started forming fruits, turn your plant's energy into growing those fruits and pinch away new buds.

Common Problems With Luffa

Growing luffa plants is easy, but they need six to seven months to grow, mature, and dry on the vine.

Yellowing Leaves and Stems

Watering issues are the biggest reasons for plant yellowing. When luffa plants are overwatered, the roots can't absorb more water due to oversaturation. Likewise, an underwatered plant needs more water to thrive.

Luffa Fruit Turning Brown

Luffa fruits start green but ripen and turn brown. Pick them in the green stage if you eat the young fruits. Brown is good when it comes to growing luffa fruits for sponges. Pick them all off the vine before the first frost.

Fruits Are Not Growing

If your luffa plant has flowered, but no fruits are starting to form, it could be that you do not have enough female flowers or your female flowers are not being pollinated. You can attempt to increase female flower production by adding phosphorus-enriched fertilizer, or if bees are not reaching your flowers, hand pollinate the flowers.