You can’t put that in a worm farm!

Common knowledge says that there are certain foods you should not feed to a worm farm. By searching around, we know that bread, meat products, onions, pineapple and other things are really bad for our squirms.

Or are they?

Worms have been eating organic material for a few year now, so it’s reasonable to say that they can probably eat all the things that we shouldn’t put in. However, the experiment is massively interesting to see played out.

There’s a group of people on Facebook called Experimental Worm Fun. Their credo is:

We have all heard you can and can’t or should and shouldn’t, as it applies to worm composting. One of our goals is to put those supposed limits to the test. Another of our goals is to share the testing and the results with anyone.

One of the members has been experimenting with feeding onions to her worm bin. Lilia has been trying to safely compost the onions with worms.

onions worm bin experimental do not feed
The Experimental Onion Bin

Lilia is not only running the experiment, she’s regularly videoing the process. We can see the progression and her success as the worms are fed only onions.

Some points from the videos:

  • Lilia is using egg shells for acidity control and also for the worms to use in their gullets to aid digestion. As she points out; make sure you really smash the egg shells into a powder so that the worms can use it.
  • Set up the bin and leave it for a week (or so) to give the worms a chance to settle in.
  • Bedding is made up of shredded paper and cardboard. Worms love this and it will also soak up the juice that is produced as the onions breakdown.
  • Feeding only in one part of the bin gives your worms a chance to hide in another part of the bin if conditions are unsuitable.
  • Only add small amounts initially. In this case, one ounce (28 grams) of frozen and thawed onion. Small amounts of other food scraps are included, in case the worms really don’t like the onion.
  • Sprinkle with egg shells to help control acidity initially. You could also add a generous amount of egg shells when you feed the initial onion to the bin.
  • Burying the onion in the bedding also helps to control the smell of the onion.
  • After only four days Lilia has some “brave souls” checking out the onion!
  • One week in and the worms are definitely at work on the onion.
  • Further checks indicate that the onions take longer to break down, but the worms are eating it with no problems or side effects.
  • The bins do not smell beyond the initial stink of the onions that are added. After that there is no bad odor of onion coming from the bin
READ  Why should I compost with worms?

So, should I feed a bin purely on onions? The answer is … maybe? Lilia is running a controlled experiment to see whether the worms will compost the onions. Generally, onions should only be added in small amounts and mixed in well with the bedding and other kitchen scraps. There is no reason for your worms not to eat onion. In a normal household environment, you would not be feeding your worms just onions.

The experiment is massively fascinating and I am looking forward to seeing how it progresses. You should also check out Lilia’s other playlists for more interesting experiments.

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Chief Worm Wrangler at The Gentleman Vermiculturist
Adam Jones is the Gentleman Vermiculturist. He lives in the suburb of Dingley Village with his wife, two kids, dog, cat and, according to his wife, an alarming number of worms. He uses email and can be contacted at
The Gentleman Vermiculturist can be found on Facebook and Instagram as well as other social media. He talks incessantly about worms.
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