Key takeaways
- A standard 300-litre plastic bin suits most UK gardens, and many councils sell them cheaply
- Mix roughly equal amounts of greens (grass, peelings) and browns (cardboard, dry leaves)
- Keep it as damp as a wrung-out sponge
- Turn it every few weeks to speed things up and stop smells
- Leave out cooked food, meat, dairy, diseased plants and perennial weed roots
- It's ready in about 6-12 months, when it's dark, crumbly and smells earthy
Composting is the easiest way to improve your soil. You turn kitchen scraps and garden waste into dark, crumbly stuff that feeds plants, helps clay drain and helps sandy soil hold water. Every garden makes enough waste to get started. You don’t need special skills or kit, and it works all year round.
Here’s how to set up a bin, what to put in, how to look after it and how to use the finished compost. It works in a big garden or a small urban plot. The Garden Organic composting guide is a good companion read, and there are more practical guides in our how-to section.
Choosing a compost bin
A 300-litre plastic bin suits most gardens, and bigger gardens do well with wooden bays. They all work. The difference is speed, size and how easy they are to use.
Plastic dalek bins
The classic UK compost bin. Many councils sell them cheaply through schemes like GetComposting. A 300-litre bin suits a typical family garden.
Good points: cheap, easy to set up, holds warmth and moisture, small footprint.
Downsides: awkward to turn, small for big gardens.
Wooden slatted bins
Build your own from pallets or buy one ready-made. A bay about 1m each way holds plenty. The open front makes turning and emptying easy.
Good points: big, easy to turn, plenty of air.
Downsides: takes up more space, needs building, and the wood rots eventually.
Tumbler bins
A drum on a stand that you spin to mix everything. No fork needed.
Good points: easy to turn, quicker results, sealed against rats.
Downsides: pricey, fairly small, heavy when full.
Hot composting bins
Insulated bins, like the HotBin or Green Johanna, stay hot even in winter. Some are designed to take cooked food. They get hot enough to kill most weed seeds.
Good points: fastest results, take a wider range of waste, work in winter.
Downsides: expensive, need more looking after, smaller.
Comparison
| Bin type | Cost | Size | Speed | Easy to turn? | Keeps rats out? |
|---|---|---|---|---|---|
| Plastic dalek | Low | Medium | 6-12 months | No | Partly |
| Wooden bays | Low if DIY | Large | 6-12 months | Yes | No |
| Tumbler | Medium to high | Small to medium | A few months | Very | Yes |
| Hot composter | High | Medium | Quickest | Varies | Yes |
Gardener’s tip: If you have room, use two bins. Fill one while the other finishes. By the time the second is full, the first is ready to use.
Three styles of bin: wooden bays for big gardens, a plastic dalek for most, and a tumbler for quicker results.
What to compost
Compost needs two kinds of material: greens, which are soft and leafy, and browns, which are dry and woody. Aim for roughly half and half. Getting this balance right is the most important part.
Greens
- Grass clippings (in thin layers)
- Vegetable and fruit peelings
- Tea bags and coffee grounds
- Annual weeds, before they set seed
- Soft prunings and deadheads
- Nettles and comfrey leaves, which get things going
Browns
- Cardboard, torn up
- Newspaper, scrunched rather than flat
- Dry autumn leaves
- Straw and hay
- Woody prunings, chopped or shredded
- Egg boxes and loo roll tubes
- Sawdust from untreated wood
What not to compost
- Cooked food, meat, fish and dairy: attract rats and smell
- Diseased plants: can spread the disease when you use the compost
- Perennial weed roots: bindweed, couch grass and ground elder survive and regrow
- Cat and dog poo: can carry harmful germs
- Glossy paper and magazines: don’t break down well
- Treated or painted wood
Perennial weed roots like bindweed, couch grass or horsetail can go in once they’re dead. Drown them in a bucket of water for 4-6 weeks first, and use the liquid as a feed.
Layers of greens and browns. Getting the mix right means quicker, smell-free compost.
How to build a compost heap
Pick a level spot on bare soil, start with a coarse layer, then add greens and browns in turn.
Location
Stand your bin on bare soil rather than concrete. That lets worms, beetles and other helpers move in from below. They do most of the work.
Choose a spot that’s:
- Level, so one side doesn’t get waterlogged
- Partly shaded, as full sun dries it out and deep shade keeps it cold
- Easy to reach with a wheelbarrow
- A little way from the house
The RHS suggests a sheltered spot in some shade, which avoids it getting too hot, cold, wet or dry.
Can you put a compost bin on concrete or paving?
Yes, but it works better on soil. On a hard surface, worms can’t get in from below and liquid has nowhere to go.
If paving is your only choice, put a few spadefuls of garden soil in the bottom first to bring in the helpers. Add a layer of twiggy prunings or scrunched cardboard to soak up extra moisture. Brown liquid may seep out and stain paving, so avoid pale stone. Standing the bin on a pallet helps it drain. Check the bottom more often, as heaps on hard ground stay wetter.
Do you need to add worms to a compost bin?
No. Compost worms find their own way into a bin that stands on soil.
These aren’t the earthworms you dig up in borders. They’re thin, red, stripy brandling or tiger worms, which live in rotting material rather than soil. Buying earthworms for the heap is a waste of money, as they just head back into the ground. If your bin is on paving, a handful of compost from a friend’s heap will bring some brandlings with it. Lots of red worms means a happy heap.
A compost heap also attracts birds and wildlife. Robins love picking through it for insects, and slow worms enjoy the warm, damp spot underneath.
Building in layers
Start with about 10cm of coarse stuff at the bottom: twiggy prunings, straw or scrunched cardboard. It lets air in from below.
Then add layers in turn:
- A layer of greens
- A thinner layer of browns
- Repeat
Don’t squash it down. Loose material rots faster because air can move through it. If you’re adding a lot of one thing at once, like a mower box full of grass, mix in some cardboard so it doesn’t turn into a soggy mat.
A coarse layer of twigs or scrunched cardboard at the bottom lets air in. Then add greens and browns in turn and keep it loose.
Moisture level
Compost should feel like a wrung-out sponge: damp but not dripping. Too wet and it turns slimy and smelly. Too dry and it stops rotting.
In summer, water the heap in dry spells. In winter, cover it with a lid or old carpet so rain doesn’t soak it. If it gets too wet, mix in torn cardboard.
In winter, a lid or old carpet stops rain soaking the heap. Aim for compost that feels like a wrung-out sponge.
Managing your compost
Looking after compost means turning it, keeping it damp and keeping it warm enough to work.
Turning
Turn the heap every few weeks with a garden fork. It lets in air, which the tiny creatures doing the work need. Move the outside bits into the middle, where it’s warmest.
After getting the mix right, turning makes the biggest difference to speed. Regularly turned compost can be ready in a few months, while unturned heaps take closer to a year.
Turning a dalek bin is a bit awkward. Lift the bin off, set it down next to the heap and fork everything back in.
Temperature
A busy compost heap warms up as it rots. You can often feel the heat if you push your hand into the middle.
Hot composting means keeping the heap really hot on purpose. It kills weed seeds and gives quicker compost, but takes more effort: a big heap, the right mix and frequent turning.
Cold composting is what most of us do. The heap stays cooler and breaks down slowly. Weed seeds can survive, so don’t add weeds that have gone to seed.
Activators
Activators are things that get a heap going:
- Fresh nettles (free and brilliant)
- Comfrey leaves
- Grass clippings
- Urine (yes, really)
- Shop-bought activators, though you don’t need them if your mix is right
Turning a heap with a fork. Moving the outside into the middle speeds things up.
Troubleshooting
Most problems come from too much water, too little air or the wrong mix of greens and browns.
Slimy and smelly
It’s too wet and short of air. Mix in browns like torn cardboard, scrunched newspaper or dry leaves, and turn it. It should sort itself out in a week or two.
Dry and nothing happening
It’s too dry. Water it well and mix in some greens. Cover it to keep the moisture in, and water it in dry summer spells.
Rats and mice
Rats come for food. Slugs like to hide around bins too. Stop adding cooked food, meat and dairy. Make sure the bin sits flat with no gaps underneath. Wire mesh under the bin stops digging, and a sealed tumbler keeps them out completely. Our guide on how to get rid of rats has more ideas.
Ants
Lots of ants means the heap is too dry. Water it well and turn it, and they’ll soon move on.
Very slow
Pieces might be too big (chop or shred them), there may be too many browns (add greens), the heap might be too small, or it’s just cold. Things always slow down in winter and pick up in spring.
Using finished compost
Finished compost is dark, crumbly and smells like a woodland floor. You shouldn’t recognise anything that went in. It usually takes 6-12 months.
Soil improver
Dig it into beds before planting, roughly a wheelbarrow load for every 3 or 4 square metres. It helps every kind of soil. It’s one of the best things for improving clay soil, and it helps sandy soil hold water and food. It perks up tired soil in shady borders under trees, and it’s the foundation for growing vegetables and the whole garden-to-table approach. Fruit trees love a yearly compost mulch too, including apple trees and pear trees.
Mulch
Spread a 5cm layer around established plants in spring, keeping it off stems and trunks. It keeps weeds down (including common lawn weeds creeping in at border edges), holds in moisture and feeds the soil. It’s a big help for low maintenance gardening and in raised beds.
Homemade potting mix
Mix sieved compost with sharp sand and perlite in roughly equal parts for pots. It drains well and feeds container plants. It’s too rich for sowing seeds, which prefer a finer, lower-nutrient compost.
Lawn top dressing
Sieve it fine and scatter a thin layer over the lawn in autumn. Brush it in with a stiff broom. It feeds the grass and helps fill small dips.
Finished compost: dark, crumbly and smelling like a woodland floor.
Should autumn leaves go in the compost bin?
A few are fine as browns, but big piles are better made into leafmould separately. Leaves rot slowly in their own way, and a bin full of them can take up space for well over a year.
To make leafmould, rake leaves after rain so they’re damp. Pack them into black bin bags, poke a few holes with a fork, tie the tops and tuck them out of sight. For lots of leaves, make a simple pen from chicken wire. Oak, beech and hornbeam leaves rot down in one to two years. Tough evergreen leaves like laurel and holly are very slow, so shred them or leave them out.
Leafmould isn’t rich in food, but it’s a lovely mulch and soil improver, and great in seed-sowing mixes.
Big piles of leaves are better in their own pen. Pack them in damp and in a year or two you’ll have lovely leafmould.
Month-by-month composting calendar
| Month | What to do |
|---|---|
| January | Keep adding kitchen waste. Don’t turn in frosty weather. |
| February | Save up browns for the spring grass rush. Check it’s not too wet. |
| March | Things wake up as it warms. Give it the first turn of the year. |
| April | Mowing starts. Mix clippings with cardboard. |
| May | Lots of greens. Balance with browns and turn regularly. |
| June | Check it’s not drying out. Water if needed. |
| July | Quickest rotting time. Take finished compost from the bottom. |
| August | Keep turning. Add soft prunings and deadheads. |
| September | Add spent crops, but leave out anything diseased. |
| October | Shred autumn leaves to use as browns. Bag spares for winter. |
| November | Cover the bin with old carpet. Turn less often. |
| December | Just add kitchen waste. |
Common mistakes
The usual slip-ups are too much grass at once, never turning it and expecting results within weeks.
Too much grass at once
A thick layer of fresh grass turns into a slimy, smelly mat. Always mix grass with browns, and add it in thin layers.
Expecting quick results
Composting takes months, not weeks. Lots of first-timers check after a fortnight and think it isn’t working. Be patient.
Putting the bin in deep shade
A bin in deep shade stays cold and rots slowly. Partial shade is ideal, with a bit of morning sun to warm it.
Never turning it
Unturned compost gets squashed and airless. It still rots eventually, but slowly and smellily. Even an occasional turn helps.
Adding diseased plants
Blighted tomato plants, clubroot-infected brassicas and other diseased material shouldn’t go in a home bin. Home heaps rarely get hot enough to kill the disease. Put it in your council green waste instead, which is composted at higher temperatures.
Now you’ve mastered making compost, read our guide on improving clay soil to put it to great use in heavy UK soils.
Frequently asked questions
How long does it take to make compost?
Usually 6-12 months in an ordinary bin. A carefully managed hot heap can be ready in a few months. It’s quicker if you balance greens and browns and turn it often. Summer is faster than winter.
What should you not put in a compost bin?
Leave out cooked food, meat, fish and dairy. They attract rats and smell. Also skip diseased plants, perennial weed roots like bindweed and couch grass, cat and dog poo, and glossy paper. Most other garden and raw kitchen waste is fine.
Can I compost grass clippings?
Yes, grass is great for compost. It’s rich in nitrogen and rots down fast. Mix it with browns like torn cardboard or dry leaves, or it turns into a slimy, smelly mat. Add it in thin layers rather than a big dump.
Do I need to turn my compost?
You don’t have to, but it really helps. Turning lets air in and speeds things up a lot. Aim for every few weeks. Unturned compost still rots down, just much more slowly. Use a fork to move the outside bits into the middle.
Why does my compost smell bad?
It’s too wet or short of air. Mix in browns like torn cardboard, scrunched newspaper or dry leaves, and turn the heap with a fork. The smell should go within a week or two. Healthy compost smells earthy, like a woodland floor.
How do I know when compost is ready?
It’s dark brown, crumbly and smells earthy. You shouldn’t be able to tell what any of it used to be. Sieve out any big lumps and put them back in the bin to carry on rotting.
Can I compost in winter?
Yes, just keep adding to it. Things slow right down in the cold but pick up again in spring. Covering the bin with old carpet or cardboard helps keep a bit of warmth in.
Our team produces practical UK gardening guidance from source research, contributor records and established horticultural practice. Editorial standards are overseen by Matt W.
