Growing luffa (sponge gourd) plants requires a certain amount of patience. It s not a typical garden plant. It grows for a longer time than most gourds. Sometimes the seeds can be slow to germinate. Luffa is a hot weather plant and growth slows in cool weather. The flowers appear over an extended period of time blooming sequentially as the vine progresses.
The vines can grow 30 feet(10 m) long over the course of a growing season. Once the fruits form it may take a long time to fully develop fibre and dry for harvest. Then the work of picking, peeling, and cleaning happens late in the year. Luffa requires about 150 to 200 or more warm frost free days, depending on the location and variety grown.
Common name: luffa
Height: 5 to 6 feet
Difficulty level: Easy
Planting & Care
It needs lots of sun, warmth, water, good root nutrients, and a large strong trellis. The vines will grow on the ground on a well drained weed-free flat surface but tend to produce curved loofahs. Luffa can also be grown in containers around 5 gallon size. Containers must have good drainage and can t be moved once the vines attach tendrils to other objects.
A small pot starter trellis can be used in the container until it is permanently located. The ideal soil pH is neutral to slightly alkaline. Some lime might be needed for acid soils.
Sunlight: Part to full sun
Soil: When preparing a site for planting ridge gourd seeds, amend the soil with organic matter, such compost or composted manure. You can spread a 2-inch layer of organic matter on the site and work it the soil as a depth of 6 to 8 inches. A soil pH of 6.5 to 7.0, or neutral to slightly alkaline soil, is used for growing ridge gourds, but do not add lime unless a soil test determines a low pH.
Water: Keep plants moist, but not saturated.
Temprature: It grows best in air temperatures between 60 and 75 degrees F.
Fertilizer: It needs a fertilizer high in phosphorous and potassium than nitrogen. Bottle gourds need nitrogen to grow vigorously, but excess nitrogen will encourage more leaves instead of fruit. A NPK fertilizer with ratio of 6:10:10 or 4:8:5 can be used. Add about 20 g in the soil for each plant before planting.
Feed every 2 weeks with a liquid fertilizer or comfrey tea fertilizer.
- Luffa can be grown by directly planting into the ground in warmer climates, USDA zones 7 and higher.
- Plant 3 to 4 seeds per location about 3/4 inch deep in well drained soil.
- Starting seeds early in pots early often gives better germination and can provide an early start on the growing season.
- Space plantings a minimum of 3 feet(1m) apart.
- 6 feet(2m) is much better.
- Average soil temperature must be around 70 degrees F (21C) or warmer for seeds to sprout and plants to grow.
- For areas where the growing season time is marginal, starting the seeds in pots well ahead of the last frost date is a better choice and is highly recommended for zone 6 growers.
- Seeds often vary in size and the planting depth should be deeper for larger seeds.
- Plant 2 or 3 seeds about 1/2 to 3/4 inch deep in potting soil.
- Germination speed and growth is very dependent on soil temperature so place pots in a warm place.
- Keep the soil moist but not too wet.
- Germination time can vary widely.
- It could take weeks.
- Typically it is 7 to 14 days but can be as short as 4 or 5 days for fresh seeds in ideal conditions.
- Luffa seed germination rates can vary widely, about 50 to 80% for ideal planting conditions.
- Some seeds may take longer than others from the same batch.
- Applying some nitrogen fertilizer to the seedlings will help keep the plants green.
- Thin plants to one per pot or planting location.
- The seedlings grow slowly while the roots develop.
- Provide lots of sun and don t let the soil get too dry.
- Small pots may need water every day but don t over water.
- The plants can t survive muddy waterlogged soil.
- These plants were started in 4 inch(10cm) pots which is good for about a one month early start.
- If the luffa plants will be in pots for longer than a month a 5 or 6 inch(13-15cm) pot would be better.
- A small pot trellis may be needed when starting plants inside more than a month early.
- Once the seedlings send out the first normal leaf or two, the luffa plants are big enough to transplant.
- The roots by this time may be 6 inches (15 cm) long or longer.
- Wait until all danger of frost is passed and the soil is warm.
- Cool overnight air temperatures don t seem to hurt them but an extended cold spell can stop their growth.
- The average soil temperature needs to be warm enough.
- Luffa are somewhat sensitive to transplant shock so be careful when planting.
- Leaving the plants outside a couple days before planting helps them to adapt.
- Luffa plants prefer good well drained soil but tolerate a fairly wide range of soil types.
- Working some organic compost into the ground before planting can help feed the roots.
- Plants need nitrogen in the seedling stage but require potash and phosphorous for blooming.
- It is best to use only nitrogen to keep the seedlings green and switch to balanced all purpose fertilizer when transplanting outdoors.
- If the smaller plants receive too much potash and phosphorous they may bloom prematurely.
- This will result in many early small loofahs on spindly vines as the plant tries to put energy into pod formation instead of growing the big vine it needs for big loofahs.
- While the luffa plants are small they are vulnerable to weeds and pests.
- It is important to keep the weeds off them.
- Shade from weeds will stunt the plants at this point.
- Slugs can damage the small stems.
- Birds may snip off pieces.
- Too much rain can drown them.
- Black plastic or dark mulch around the small luffa plants will help warm the soil and reduce weeds.
- Mulching increases yields in the long term.
- Once the plants begin to bolt and grow larger, the luffa vines are tough enough to mostly fend for themselves.
- The vines will climb over most obstacles.
- The luffa vines must have a strong trellis system to climb.
- We grow most of ours on chain link fence because it is already there.
- The vines prefer to grow much taller and will do better on a 6 to 10 feet (2-3m) high trellis.
- The vine length can exceed 30 feet(9m).
- After the vines bloom pollination has to occur before a pod will form.
- Bees of all types are attracted to the big yellow flowers and perform much of the work.
- Ants also spend a lot of time on luffa vines.
- There are small triangular leaf-like structures at the base of the flowers that attract ants.
- The blooms will fall off and the pollinated ones will form the start of a loofah sponge at the base of the former female flower.
- If pollinating insects are in short supply the flowers can be hand pollinated.
- Pull off a male flower and gently rub it on the females or else use a cotton swab to move pollen between flowers.
- The female flowers are the solitary large stemmed ones.
- The males are located in clusters of buds with thin stems.
- Both flowers are large and yellow.
Harvesting: This can be the most enjoying part of growing gourds. At Foothills Farm, we normally wait until after frost and the gourd vines have died. After this, it is very easy to find and harvest the gourds. If you want, you check the gourd patch before frost and see if any gourds have already started to dry on the vine. It is okay to harvest these before frost.
- Caring for luffa is very similar to caring for cucumbers or melons.
- Keep plants moist, but not saturated, and provide sturdy support for best results as part of your luffa plant care.
- Once the plants begin to grow, you can remove all the first flowers, any male flowers and the first four lateral branches.
- This will result in stronger fruit.
- Remove luffa fruit from the vine before the first frost.
- Follow instructions for cleaning and preparing the fruit, depending on how it will be used.