Growing Luffas

I’ve decided on my new plant to grow this year. My new vegetable of choice is the luffa, or loofah as it’s also known.  They are a member of the cucumber family and as I have had a lot of success with those in the tunnel over the years I think loofas make an ideal choice. 

 

We are probably all familiar with the loofa plant without knowing it as the dried fruit is often used in the cosmetic industry. I first saw one when I was a child and the two foot length of stiff fibrous plant was in the bathroom being used as a back scrubber. At the time I thought this was very tropical looking and came to the wrong conclusion that it was from the sea and similar to sponge.

The luffa fruits are edible when young and are a popular vegetable in China and Japan and In Paraguay, panels made out of luffa are combined with other vegetable matter and recycled plastic, which  can be used to create furniture and construct houses. Loofa’s can also be used as a pan scrubber, a skin exfoliator, a metal cleaning pad, hydroponic plant growing, cool looking plant pots and as a painting tool.

The sap from the plant also seems to deter pests and the flowers will attract a lot of pollinators.  The powdered luffa fibers have been an ingredient in traditional Chinese herbal medicine. One Egyptian study found the seeds of luffa reduced blood glucose levels in animals, but I’d consult the experts if you were using the plant for this purpose.

Varieties and plant material

There are two species of luffa – Luffa acutangula, best for flavour, which looks like a fluted green barrage balloon about 28cm/10in long and L..cylindrica, which looks very similar to a courgette, except that the skin is smooth, shinier and fairly hard rather than slightly bristly. Both have similar leaves, deeply lobed and sprawl rather than climb, using tendrils. The flowers look similar to a courgette and can also be eaten; we deep fry our courgette ones in batter.)

Planting

Luffas need a long growing season so I’ll need to plant now (April to May). There is some evidence that soaking the seed for 24 hours in lukewarm water before sowing encourages germination.

Emergence rates are often low even with fresh seed, so I’ll plant twice as many as I need. I’ve been told they can get heavy so I’ll see how they do running along the ground, it this takes up too much space I can tie them to the frame of the polytunnel, if they are anything like cucumbers they won’t climb particularly well and might need a bit of help.

Easy Care

Established plants can grow to 7m/22ft but often reach less. Luffas aren’t very demanding in their soil requirements thankfully , and don’t need as rich a soil as other cucurbits, but once flowers appear weekly feeding with comfrey liquid should improve the fruiting. 

Male and female flowers are carried independently on the same plant, but in poor conditions only male flowers may develop.

A well-grown luffa plant can support about 6 or 7 fruits to maturity, although as with courgettes if you keep picking the plants will continue cropping throughout the season.

Healthy

Luffas are reasonably healthy but can suffer from the same problems as other cucurbits, especially powdery mildew if the weather conditions are suitable, especially during late summer with humid nights and dry soil. Watering the plants well and removing the worst affected leaves will help control the disease. Plants grown indoors can be prone to develop spider mite infestation in hot summers, so I’ll need to look out for the signs.

Harvesting and storage

It looks like luffas for eating are better when they are 30cm/12in long, as otherwise they become tough and bitter. Some seeds sold for growing here may taste bitter anyway, because they are for strains selected for sponge production. Peeling and sprinkling the cut flesh with salt may help remove some of the bitterness but if you find you have one of these you might as well grow yourself a back-scrubber rather than try eating the inedible.

It looks like the fun bit of growing them for scrubbers is to wait until the skin is hard and just turning colour if you want a pale coloured sponge, or allow the gourd to turn brown if you want a dark-coloured fibre. The skin is hard but brittle so throwing the fruit hard against a brick wall or concrete path is an easy and rewarding way to crack it. Then peeling off the split skin using a sharp knife and rinse the pulp under a running tap outside until the seeds and skeleton of fibre are revealed seems to be the popular way of revealing the fibres. 

If the remaining fruit is placed in a bucket of cold water to soak for a week the remaining flesh will begin to rot and can be removed completely, revealing the cleaned loofa. Combine this with a piece of soap and you have the perfect present for people.