When to Harvest Luffas

Luffa Flower

Luffas or Loofahs are a really fun crop to grow and a great sustainable alternative to plastic too. Many people don’t associate those lovely sponges we use to exfoliate our skin in the bathroom with plants (I remember thinking they were sea creatures as a kid!). But once you discover you can grow your own you will never buy another luffa or kitchen sponge again (and you’ll likely have enough for your friends and family too!). Not only are they prolific, they are also beautiful plants with huge tropical-looking leaves and wonderful yellow flowers.

It’s that time of year; everything is coming indoors to keep it from catching the frost. Luffas are no exception! The growing season is coming to an end here in the UK for tender crops and its important not to get complacent, even with our indoor crops. Polytunnels and greenhouses are no match for a heavy frosts sadly.

Luffa Seedling

Luffas need a really long growing season, so I start mine off in late February / early March. I took mine in this week (early November) and they still haven’t quite ripened up. One was perfectly ready, but the rest have had to come in prematurely to protect them from frost. The good news is that they will dry out at home and I’ll be able to harvest the sponges inside soon.

So when are luffas ready to harvest? This is a pretty good question, and if you have got this far its likely that you are pretty invested in not getting this last part wrong! So, as I’ve said before, take them off the plant either when they are dry and “ready” OR before they are burned by frost. They will start off green, hard and heavy. As they dry out, the skin will start to become squashy. Gradually, they will become lighter as they dry out and the skin will start to turn yellow. They will then develop brown patches. when they are starting to turn brown they are ready to harvest.

We harvest the internal skeletons that are made out of a really tough polymer called lignin. Lignin does not break down very easily which means that whilst the rest of the fruit dries out and disintegrates, the lignin skeleton remains. To harvest the skeleton all we need to do is cut from the top of the gourd to the bottom through the skin (taking care not to cut the skeleton too). Then we simply peel off the skin and voila! The skeleton comes out super easily. If you harvest the skeletons from inside the fruit too early you may well be left with a very big clean up job – and these things don’t smell good!

It may still be a little slimy and a have little pieces of flesh on it, so I take them home and wash them in a tub of warm water, giving them a squeeze all the way down to clean them. When they have dried (which can take a day or so!) the seeds will shake out easily too and (hurrah!) you will have seeds for next year too!

The most important thing to remember about growing luffas is that they are a warmth-loving plant. They need to be grown inside in the UK with as much heat as you can give them. Make sure you start them early and have a big enough space for them. But most of all – harvest them correctly!

Check out this video of me harvesting my luffas:

Published by sowmuchmore

Ecologist and Botanist by training, now most often found pottering around my no dig kitchen garden. I love sharing gardening tips and advice based on science, and teaching people how to employ plants and nature to work for you

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