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How to make a tyre stack compost bin

When you grow your own food, compost is always at a premium. Because it is rat-proof, a simple tyre stack worm composting bin allows you to compost even things you couldn’t put in a regular composter because of the risk of attracting vermin; bread, rice, meat, fish, dairy, and anything that has been cooked. In the winter, even raw food scraps may tempt rats to move in, leaving you no option but to throw good organic material away: if you’d rather not, a worm bin may be for you.

One note of caution: old tyres may be free, but using them in your plot cannot be considered organic. Zinc and other chemicals have been shown to leach out of ‘crumbed’ tyre rubber and, although the risks for whole tyres are thought to be much lower, those leachate chemicals will still be there in tiny amounts. If the thought of that worries you, this design isn’t for you. That said, a simple five-tyre worm bin is entirely free to make, and will eat all the bits of food waste that can’t go on a regular compost heap. So, here’s what you need:

  • A large paving slab (or use pre-existing hard standing). Freecycle is always full of them.
  • Five used car tyres. Any local tyre dealership will be amazed you want them.
  • Some stiff wire, such as an old coat hanger.
  • A bin lid, or similar. This is the tricky bit – keep your eyes open.

First, choose a level spot that will have some shade in the hottest part of a summer’s day. Unless you modify the design to collect the nutritious liquor the worms produce, then this will run into the surrounding soil – so it makes sense to place your bin in the shade of a deciduous tree.

Make the base

Put down a hard base such as a paving slab. This provides a rodent-proof bottom for the bin, and so needs to be big enough to make contact with the bottom tyre all the way round. Make sure that the slab is approximately level so that the bin does not lean, but allow a little slope for drainage.

tyre composter under construction, image

Prepare the tyres

Pack the rims of the tyres loosely with “brown” composting material. This provides a low-nitrogen, high-oxygen bedding area for worms that are not feeding. You can use dead leaves, hay or straw, dipped in water and then allowed to drain. Alternatively if you’re re-building an existing bin you can use some compost from the old one. In these photos I used spoiled straw, simply because I had some to hand.

tyre composter under construction, image

Build the stack

Put one of the tyres in the middle of the base to form the bottom of the stack, and load it with starter. This is a bucketful of material already rich in local composting worms, and there’s no need to pack it down as the action of the worms will do this for you. There are firms around who will sell you hugely expensive “starting packs” of worms or worm cocoons, but there is nothing magical about them and you do not get many; far better to ask a friend or neighbour for a bucketful of compost that’s just at the finishing off stage, when there are plenty of worms in evidence anyway. These worms are native to your area, and appear like magic when there’s work to be done.

Place the tyres in a stack, making sure it is properly upright. There’s no special reason for the stack being five tyres high, other than it makes it a convenient height for most people; you could just as easily use six. However, this won’t make the bin work any faster – that is governed by the number of worms, surface area, temperature and what you feed it with. You can always make a second bin!

Secure the top

Add a lid to the top, and secure it. An old bin lid is ideal for this since it has a handle to loop an old bit of bungee cord through, but whatever you use make sure that it is big enough to shed water away from the middle in a rainstorm. The lid needs to be secure to stop rats from pushing it aside, but a couple of bricks and a piece of board work just fine. The bungee is hooked into two U-shaped pieces of strong wire which are pushed between the tyres, but you could just run a bit of bamboo through the middle of the bin and tie a length of baling twine from one side to the other. And that’s it, you’re done.

A bin like this is fairly robust and the worms will put up with a lot – there’s no need to coddle it the way you would a smaller worm bin. Having said that, don’t add too much food at once (a two inch layer would be as much as the worms can cope with) and don’t put much citrus peel in because the worms hate it. Top the food off with a few handfuls of finished compost or topsoil. When you see worms roaming about on the surface, they’re ready to be fed again.

When the bin is eventually full, take the top tyre off carefully and keep it, and the compost in it, on a sheet of plastic while you empty all the rest of the compost from the other tyres. It should essentially be finished but may benefit from a bit of a rest, and should then be treated as a fertiliser for top-dressing or soil amendment, rather than as a growing medium: it’s just too rich to use neat. Finally, use the top tyre and the compost that was in it as your new bottom tyre and starter, and rebuild the rest of the bin.

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6 Responses to “How to make a tyre stack compost bin”

  1. Mark says:

    Tires leach too many chemicals into the compost so I wound’t use them, personally. I use a sturdy cardboard box. When it’s half full, I remove all the worms and throw the whole thing into the compost bin.

    • Andy McKee says:

      I researched the whole tyre leachate question pretty thoroughly when writing the article. The leachate question is directly linked to the surface area of the rubber, so it’s only really dangerous as rubber dust (which is kicked out when you drive on them!) or when they’re disposed of improperly. As actual tyres, there are only ‘anticipated contaminants’ – the actual amounts are too tiny to demonstrate in field conditions. Having said that, the Soil Association decided to outlaw them in certified organic systems, hence the warning in the article. If you want to read more, check out the Environment Agency’s website.

  2. jase says:

    Hi, thanks for the article, I enjoyed it and found your comments re toxins from the tyres reassuring, as I have been a big fan of the tyre stack worm farm for many years!

    A few points I would add from my own experiences:
    Worm farms are much less temperamental if they are in contact with the underlying soil(better drainage and the worms can come and go if they need to), so a solid paver base is not the best idea. I set a ring of bricks or small pavers into the ground that the bottom tyre sits on- still rat-proof but with a circle of uncovered earth in the middle.

    Also very important in my experience is the regular addition of generous amounts of balled up sheets of newspaper or dry leaves. This helps hugely with aeration, and means you can put really large amounts of waste into the stack with no problems at all, and is a handy way of using up old newspaper and getting rid of dead leaves. I put in all scraps, including the supposedly troublesome onions, citrus, dairy and meat with no problems whatsoever, and I have never needed to add any compost or soil as you suggest.

    I also disagree that you need to start with a bucket of compost. Putting a layer of leaves or dead grass in the bottom tyre will bring in the tiger worms from wherever it is that they come from in no time at all, and then you’re ready to go.
    My last tip is a strange one- I use a thin metal oven tray to slide between the tyres when I want to take the bottom tyre out to get the worm castings. It works really well.

  3. Andy McKee says:

    Thanks Jase, some really good tips there! I especially like the metal tray one, and I’ll try adding some leaves or paper and see if I get a layer of lighter compost than usual. You should probably read Mark’s comments on our biodegradable pots article, though.
    A solid base doesn’t seem to be a problem for worms coming and going (they also climb!), although in those circumstances a starter bucket is a really good idea. Drainage is only a problem if the base is dead level… I’ve removed a mention of ‘existing hard standing’ because that’s when drainage might become an issue.

  4. David Laszlo says:

    For the bottom under the tyres, consider using a robust wire grid of the sort easily obtainable from garden superstores. Not chicken wire, it needs to be the tighter more heavy duty type. If there is a good contact between soil, grid and tyres all the way round, rats can’t get in and drainage is maximised.

  5. Louis says:

    I have been composting for years in base-open onto-soil compost bins. I just place a large square of chicken wire on the ground and the compost bin on top of that. As long as the edges of the chicken wire are well away from the sides of the bin (or tyre stack) There is no way for vermin to dig their way under.

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