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Send your worms and plants to work on an egg!

Those of us of a certain age *cough* will remember the Go to work on an Egg ads run by the British Egg Marketing Board.

Eggs are a natural source of protein, vitimins and minerals and can be a useful element of any healthy, balanced diet.

What these ads didn’t tell us though, was what to do with all those egg shells we generated, after we’d eaten our egg and gone to work.

One answer would be to put them to work too.

Egg shells are rich in calcium carbonate but also contain zinc, sodium, potassium, manganese, iron and copper. We all know humans and animals need calcium for healthy growth, but how many stop to think that plants also need calcium?

Plants need calcium for healthy bones and teeth….

…(just checking you were paying attention!).

No, plants use calcium for healthy cell development and growth. The stronger the cell, specifically the cell wall, the better the plant is able to resist disease. But it gets better! Calcium plays many other roles in the life of a healthy plant, including regulating the uptake and movement of nutrients into the root and throughout the cells within the plant. Who knew?

So let’s recap – egg shells are in the region of 95% calcium carbonate and have many other useful elements; plants need calcium – so we have no excuse to ever throw away an egg shell again, where it could end up in an anerobic stench trench in landfill.

What do we do from now on? We compost them or feed them to the worms, that’s what we do. And here’s how:

Feeding your egg shells to worms

Egg shells perform two functions, apart from being a source of calcium, in the worm bin. They help reduce acidity, something worms don’t like, since calcium carbonate is an alkaline, and finely crushed, the worms love them, since they ingest them and use them in their gizzard to crush food.

On a hot sunny day (yeah, right!) spread out your egg shells and let the sun dry them.

Using the sun to dry the egg shells

Using the sun to dry the egg shells

In the absense of any sun you can also just let them air dry on a towel, or bung them in the oven for 20 minutes at 60 degree C, but I’d personally only bother doing that if I was going to use the ground egg shells as a source of calcium for myself.

Crush by hand and drop them into the coffee grinder. Depending on your domestic situation you may have no problem doing this, or you many want to a) do this secretly when nobody’s in the house or b) get a cheap grinder for the purpose if you’re going to be doing this a lot. Freegle and Freecycle are great places to look for secondhand, free items people are giving away and it helps keep perfectly good items out of landfill.

Weird coffee beans??!!

Weird coffee beans??!!

My worms just love well ground egg shells so I tend to grind mine quite fine. If you want yours a bit more coarse just give the grinder a shorter burst.

Egg shells well ground up

Egg shells well ground up

Well ground up like this, sprinkle a ”pinch”, just a small amount to your worm bin, each time you feed or they can be sprinkled around your plants or added to the base of the pots for the roots as you plant out.

These shells were ground quite fine

These shells were ground quite fine

Find a couple of big jars and reuse them to store your excess calcium carbonate.

Jar of egg shell calcium treats for worms and plants

Jar of egg shell calcium treats for worms and plants

If you haven’t a grinder or don’t want to use one, no problem. Just put the shells into a bag and roll a rolling pin over them several times. Or bash them a couple of times with whatever’s to hand!

Feeding your egg shells to the compost pile

  • Wash the egg shells
  • Crush with hand
  • Drop them into your compost pile and mix in well

That’s it!

The egg shells will break down slowly over time. Don’t be surprised then to find some in the compost as you’re using it. This isn’t a problem and will add a valuable source of slow release calcium to your soil.

(photography by Sorcha)



  1. top tips thanks. Our wormery is only a few months old but the bottom layer is ready & we just crushed and added the egg shells. The only thing they didnt like was my hair – maybe as its dyed.

    • londonworms says:

      Hi there, great to hear from you. I don’t know a lot about hair dyes but I understand they can contain chemicals such as para-phenylenediamine which from what I’ve read can have some rather nasty side effects especially on skin. In a reasonably wet bin there is always the danger of the chemical concotions used in hair dye leeching out and the worms, being hyper sensitive to such things will naturally avoid this area. On that basis and in the absence of any detailed research on my part I wouldn’t recommend using dyed hair in your wormery.
      Natural hair is fine, but remember it will take quite a while to break down and degrade in the bin,even with worms ingesting it and using tiny particles in their gizzard.
      It’s this slow degradation that makes hair an ideal source of slow release nitrogen for the soil if you add hair directly to the garden/flower beds/veg patch.
      I continuously find small clumps of my hair, the dogs hair and the guinea pigs hair throughout the wormbins, but in ever decreasing amounts as time goes on.
      Thanks for getting in touch and good luck with the wormery 🙂

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