I built my first pallet compost bin in 2014. It cost nothing, took three hours, and lasted nine years. The second one, beside it, is now two years old and looks like it has another decade in it. They’re not pretty, there is no honest way to make a pallet bin pretty, but they are the right size, they breathe properly, and they were built from materials that nobody had a use for.
This is not a complicated build. It involves four pallets, some wire, a hammer, and the willingness to spend an afternoon outside. The tricky bits are in the small choices, which pallets, where to put it, how to make the front access work without turning it into a carpentry project. I will go through those.
Sourcing the pallets
The first decision is which pallets to use. US Composting Council on compost benefits Not all pallets are the same.
Look for pallets stamped with HT, which stands for heat-treated. Heat-treated pallets have been through a high-temperature treatment to kill insects; no chemicals are involved. They are safe to use anywhere, including around food crops.
Avoid pallets stamped with MB. That stands for methyl bromide, a chemical fumigation treatment that’s been phased out in most of the world but still appears on older or imported pallets. MB-treated wood is not what you want sitting next to your vegetable garden.
Pallets with no stamp are usually domestic-only and untreated, which is fine but worth confirming with whoever you got them from. Avoid anything that looks oil-stained, splintering badly, or carrying suspicious chemical smells.
Where to find them: most builders’ merchants will give them away (ask, don’t take from skips without asking, some are charged-deposit pallets that aren’t actually free). Industrial estates often have signs offering pallets. Local Freecycle or Facebook Marketplace groups have a steady supply. Aim for four matched pallets, similar in size, with intact runners and few rotten boards.
Standard UK pallet size is 1200 by 1000 millimetres. That gives a finished bin of roughly one cubic metre internal capacity, which is the minimum for a hot heap.
Tools and additional materials
You will need not much.
- Galvanised wire (1.6mm fencing wire works well), about ten metres.
- Pliers, ideally with a wire cutter.
- Four 100mm galvanised screws or large nails, plus a screwdriver or hammer.
- Four short hardwood stakes or wooden posts (about a metre long), optional but extends bin life significantly.
- A handful of metal corner brackets, also optional, but the bin holds together more reliably with them.
- A spade to level the ground.
Total cost if you buy the wire and brackets new: under twenty pounds. If you scrounge everything: free.
Choosing the site
The bin wants to be in light shade. Full sun dries it out; deep shade keeps it cold. The corner of a garden that gets morning sun and afternoon shade is ideal.
It also wants to be on bare earth, not concrete or paving. Direct contact with soil lets worms and microbes move in from below, which speeds the heap dramatically. If you have only paved options, lay down a thick layer of cardboard first as a starter for worms.
Level the spot. A heap on a slope drifts and the corners pull apart.
If you can manage it, put the bin where you can get to it with a wheelbarrow, both for adding material and for emptying finished compost. The walk to the heap matters more than people anticipate. A bin a hundred metres up the garden gets used half as much as a bin twenty metres away.
The build
The simplest pallet bin is three sides and an open front. The front opens for access. There is no top, or you add a piece of old carpet or a tarp later.
Step one: stand the back pallet upright on its long edge. Brace it temporarily with the spade or a friend’s knee.
Step two: stand the two side pallets upright at right angles, slot them against the back pallet at each corner. The runners (the thick wooden blocks at the back of each pallet) should be on the outside, facing outwards, so the inside of the bin is flat.
Step three: wire the corners. Drill or punch a few holes through the pallet boards where they meet, thread the galvanised wire through, twist tightly with the pliers. Three or four wire ties at each back corner, top, middle, bottom. This is the bit that decides whether the bin holds together or sags.
Step four: drive a stake against the outside of each back corner and screw the pallet to the stake. This is the bit that decides whether the bin lasts. Without ground stakes a pallet bin tends to walk slowly outwards as the contents push against it.
Step five: the front. The crude version is no front at all; the heap stays in place because the back and sides hold it. The slightly less crude version is a fourth pallet that slots in vertically against the front of the side pallets, held by two short bolts or large hooks. You lift it off to access the heap and replace it when you’re done.
The whole build takes about three hours if you have not done it before. The second one I built took ninety minutes.
Making it last
The single biggest factor in bin longevity is whether the pallet bases sit on damp earth permanently. Pallets rot from the bottom up.
Two ways to slow that. Either rest the pallets on a bed of bricks or paving slabs raised an inch off the soil, this keeps the wood out of standing water, or build directly on earth and accept that the bin needs replacing every five or six years. I have done both. The bricks-and-bed version of my current bin is two years old and looks unchanged from new.
The second factor is what you let touch the wood. Acidic kitchen scraps directly against the pallet boards rot them faster than the contents on the inside. Line the inside of the bin with a thick layer of cardboard or old hessian sacks. This isn’t essential, but it doubles the bin’s life.
Don’t paint or varnish the pallets. Anything that traps moisture in the wood accelerates rot.
The first fill
A fresh bin works best if you start with a base layer of coarse material, twigs, broken-up garden prunings, the crusty bits of old straw. About fifteen centimetres deep, loosely laid. This creates an air pocket at the bottom that helps the heap breathe from underneath.
On top of that, alternate layers of greens (kitchen scraps, fresh garden waste, grass clippings) and browns (shredded card, dry leaves, torn newspaper). Aim for roughly twice as much brown as green, by volume, especially early on. Water lightly if the materials are dry, the heap should feel like a wrung-out sponge.
Within a couple of weeks the bin will settle by a third or more. Don’t worry, that’s composting working. Top up gradually.
My older bin is still standing, lopsided and silvery with age. The newer one is the proper modern model, bricks underneath, hessian lining, pallets stamped HT, neat wire corners. They both produce roughly the same amount of compost. The compost doesn’t much care about the construction.
Frequently Asked Questions
Are pallets safe to use for composting?
Yes, provided they're heat-treated (stamped HT) rather than chemically fumigated (stamped MB). Most pallets in modern UK supply chains are HT. Untreated domestic pallets are also fine. Check the stamp before building.
How long does a pallet compost bin last?
Five to ten years, depending on conditions. Bins that sit directly on damp soil rot fastest, particularly the bottom boards. Raising the pallets on bricks or paving slabs significantly extends their life.
Do I need to treat or paint the pallets?
No. In fact, treatments often shorten lifespan by trapping moisture. Leave the wood bare. If you want extra protection, line the inside with cardboard rather than treating the outside.
What if I can only find smaller pallets?
Smaller pallets work but produce a smaller bin. Anything under about 90cm internal width struggles to hold heat and slows composting. Try for full-size 1200x1000mm pallets if possible.
Can I add a top to keep the rain out?
Yes — a piece of old carpet, a corrugated bitumen sheet, or a heavy tarp weighted at the corners works. A solid top keeps the heap from getting waterlogged in heavy rain, which can drown the bacterial activity.
How do I empty a pallet bin with a fixed front?
Lift the front pallet off (if hooked) or unscrew one wire tie and pivot the front aside. With a fully fixed front, fork the contents up and over the front edge into a wheelbarrow. The slightly removable front is much easier; build that version if you can.
