Luffa cylindrica

Luffa cylindrica, also known as Luffa acutangula, the 'Angled' or 'Ridged' Luffa is a very versatile plant that is widely grown in Asia for eating. As a vegetable, the leaves can be eaten in a salad, the very young gourds taste like aubergine (zucchini). They are known as Chinese Okra but are not related to Okra at all.
The vines and fruits resemble a cucumber, but unlike that vegetable, luffa's gourdlike fruit, when dried and peeled reveals a fibrous, spongy skeleton so downright useful that the luffa plant is now cultivated throughout world.

The matured dried gourd develops into a fibrous netting. It is an excellent sponge and makes wonderful skin scrubs and exfoliators. They are also useful for washing dishes, the car or windows and have industrial applications such as for water filters. They can last for years and are easily cleaned in the washing machine.

Luffas are easy to grow but require a long growing season of frost free weather. But for those in colder climates, seedlings can be started early indoors and then transplanted outside. The vine can grow to great lengths producing beautiful yellow flowers all summer.

Sowing:
Store seeds until planting time in their packaging in a cool, dark, dry place. (Do not refrigerate) Sow indoors at temperatures above 20°C (68°F). The plants need a long growing season to get a good crop of sponges.
Soak seed for two hours in warm water before sowing. Fill small pots with a good free draining seed compost. Stand the pots in water until the medium is completely moist. Place seed on the surface and press into the compost. Cover with a sprinkling of compost or vermiculite.
Bottom heat is helpful, place in a propagator if you have one or seal the container inside a polythene bag and place in a warm location out of direct sunlight. Do not exclude light at any stage as this is beneficial to germination. Germination usually takes 7 to 21 days at 20 to 30°F (68 to 86°F).

Cultivation:
Plant out in early summer, after all risk of frost has gone. The plant can often survive in partial shade with some direct sunlight but grow better in full sun. In a very hot dry climate they will need some watering as they tend to wilt if it gets too dry. The vines are easy to grow with no insect problems but will benefit from the application of a fertiliser with high nitrogen content once a month after the flowers appear.
The Luffa plant is a fast-growing, long-season, warm-climate vine plant that can climb up to 4½ metres (15ft) high. Support the vine on a strong trellis or fence. A strong supporting trellis or fence is a must. The more support points the better.

Pollination:
Luffa plants need insects to carry out the pollinating process for setting fruits. If the insects or bees are not available in your area, the pollinating process can be done manually, by picking up male flowers and transferring pollens to female flowers (by face-to-face touching the center part of flowers). This process should be carried out when flowering is active during the daytime.
The plant is monoecious, that is, it has both male and female blossoms on the same vine. The male blooms drop, while the females remain attached to the developing fruit.
Once pollinated, the fat portion of the female flower will grow into full size fruit. The vegetables fairly rush toward maturity, growing at the rate of about 4cm (1½in) a day.
Many varieties could perform relatively poor during the long day season in early summer and perform much better during the late summer and autumn when the shorter daytime season arrives.

Harvest:
The fruit is edible only when immature. Harvest tender young fruits, 15 to 40cm (6 to 15in) long is ideal for eating, approx 100 days after sowing the seeds and harvest for sponges approx 30 days later. When picked fresh, the green loofah is slightly softer than a cucumber and slightly crispier than an aubergine (eggplant / zucchini).

Culinary Uses:
The two most popular vegetable sponge species are the ridged luffa (Luffa acutangula), favoured for its tasty fruit, and the common luffa (Luffa cylindrica), usually grown for its 30 to 60cm (1 to 2ft) long gourds. Both varieties are edible.
The ridged luffa is the tastier of the two varieties, while the common luffa occasionally develops a bitter flavour. Barring any unlikely bitterness though, luffa makes a delicious table vegetable.
The Luffa is a very easy to use edible squash. Very young fruit can be sliced and added raw to salads where it gives a mild cucumber-like flavour. When the gourds are gherkin-sized they can be added to stir fry and in soups and sauces because it has the ability to soak up the flavours and add texture. It is also batter dipped and fried. But the real gastronomic utility of this vegetable lies in its ability to substitute for squash or zucchini, or for eggplant in parmigiana. And one especially hearty recipe adapted from a traditional dish using green peppers is for stuffed luffa.

Making a Sponge:
Pick the gourds once they start to turn yellow and are becoming very light in weight. Peal them as soon as possible, the longer the skin stays on, the darker the sponges will get, and where the brown spots are, becomes hard to peel and the sponge beneath is discoloured.
Cut both ends to begin to peel of the outer skin and gently tug the skin away from the sponge. Inside the spongy gourd is moist and fibrous. Squeeze it repeatedly from the middle towards the ends to remove the fleshy substance inside and the wash it thoroughly.
Plenty of large black seeds will come out – wash, dry and store them somewhere dry and cool for next year.
If the sponge is discoloured, soak it for 5 minutes in warm water with a little bleach. Dry the sponge by either hanging outdoors in fine weather or by placing in an oven at 150 degrees or so.
Sponges can be cut into sections or left whole. Add a length of hemp rope if you like to hang up your shower sponge. A large crop can yield quite a few Christmas gifts.

Origin:
The Luffa or Loofah is thought to originate in India and is commonly used for eating throughout Asia and parts of Africa. There are a number of distinct varieties of edible Luffa sold in southeast Asia and India, where the greatest genetic diversity is found. There are varieties with angular or ridged fruit and smooth cylindrical types. They are most often considered two different species. It is in the cucurbit family, along with cucumbers and is a type of gourd.

Nomenclature:
The genus name is spelt a number of ways - Luffa, Lofah, Loofah or Lufa.
The species name acutangula and common names of Angled luffa or Ridged luffa, refer to the ten strongly defined ridges that run the length of the fruit.
Luffa acutangula is known in some parts as Vine Okra or Chinese Okra, the angular varieties do look a bit like okra when harvested young but are not related to Okra at all.
In Chinese they are called Ling Jiao Si Gua, You Lin Si Gua, Sze Gwa or Sigwa. In Japan they are called Ito Uri or Tokado Hechima and in Indonesia they are Gambas or Oyong.
The Chinese common name of sin qua, means 'silk gourd', a reference to the gourds’ vascular system.