Learn / Composting methods
Bin and barrel composting: compost in a small space.
You don’t need a farm to make compost. A drum or bin in a corner of a compound, balcony or backyard can turn kitchen scraps and garden waste into dark, crumbly compost for pots, kitchen gardens and small plots.
What to expect
Four ways to compost in a container
All of them work on the same principle: give the microbes food, moisture and air, and keep the pests out.
Drum with a lid
An old plastic or steel drum with air holes drilled around it. Easy to find, easy to move, and easy to keep closed against rats and flies.
Open-bottom drum on soil
A drum with the lid and bottom cut away and air holes in the sides, set in shade on bare soil. Worms and soil life can move in from below. Keep it full.
Double-chamber bin
Two side-by-side bins built from blocks, bricks, wood or concrete. You fill one while the other matures. Leave gaps in the bottom course for air.
Tumbler drum
A drum on an axle that you rotate to mix and aerate. It is less work, but costs more. In Ghana, a steel tumbler was beyond what many periurban households could afford without help.
SOURCES: CONTAINER COMPOSTING (KUMASI, GHANA); “MAKING COMPOST IN A STEEL DRUM” BASIC GUIDE
Step by step
- Pick a safe drumUse a plastic or steel drum of about 200 to 250 litres. Do not use one that held chemicals, pesticides, fuel or anything toxic.
- Make air holesDrill plenty of holes around the sides, spaced about a hand-width apart, and near the base for drainage. Keep each hole under 1.2 cm so rats can’t get in. A lid with a few small holes also helps.
- Raise it and catch the drainageIf the bottom is closed, stand the drum on bricks with a tray underneath to collect the liquid that drains out. If you cut the bottom out, stand the drum on bare soil.
- Put it in the shadePlace it in a shady spot near your kitchen or garden, so it doesn’t dry out and so it’s easy to feed.
- Start with dry materialPut a layer of dry browns in the bottom, such as dry leaves, straw or shredded cardboard, then moisten them.
- Feed it in layersAdd kitchen scraps and other greens, then cover them with a layer of browns. Repeat. Chop or shred everything first, because small pieces rot faster.
- Close the lidKeep it shut to keep out rats and flies, and to stop heavy rain from waterlogging it.
What goes in, and what stays out
| Browns (carbon) | Greens (nitrogen) | Keep out |
|---|---|---|
| Dry leaves, straw, dry grass, shredded paper and cardboard, coffee filters, wood shavings, eggshells, chopped woody prunings | Vegetable and fruit peelings, grass clippings, green leaves, young weeds, flowers, tea leaves and bags, coffee grounds, herbivore manure | Meat, bones and fish, dairy, grease, dog, cat and bird droppings, diseased plants, invasive weeds, sawdust from treated wood. Sticks and brushwood take too long to rot. |
Getting the balance right.
For the fastest method, some guides suggest roughly equal volumes of browns and greens. Kitchen scraps are very wet, so most bins need more browns than that. If in doubt, start with two to three parts brown to one part green, as in What is compost?, and adjust by smell and feel. Feed little and often: filling a bin too quickly compacts it and makes it rot.
SOURCES: UC MASTER GARDENERS (SACRAMENTO); CONTAINER COMPOSTING (KUMASI); “MAKING COMPOST IN A STEEL DRUM”
Moisture, mixing and timing
- Moisture. Keep it about as damp as a wrung-out sponge. In dry weather sprinkle water (kitchen wastewater works). Too much water makes mud, and too little leaves it mouldy and half rotted.
- Mixing. Stir or turn the contents to bring in air. A sharp stick or a garden fork works for a bin you can’t tip.
- Burying scraps. Push food waste 15 to 30 cm into the middle of the bin so flies don’t find it.
- Drainage. Dilute any liquid you collect about 1 part to 10 parts water and apply it to the soil. Keep it off the leaves of vegetables you’ll eat soon.
How long does it take?
| Method | Turning | Ready in |
|---|---|---|
| Rapid | Every 3 days at first, then weekly | 6 to 8 weeks |
| Mixed | About weekly | 3 to 8 months |
| Slow | When you feel like it | 12 to 18 months |
These timings come from a US extension guide, so treat them as a rough guide. Your climate and materials will change them.
Two containers beat one.
In a closed drum or bin, fresh scraps keep restarting the process, so a bin that is always being topped up rarely finishes. Fill one container, then stop adding to it and let it mature while you fill a second. When the second is full, empty the first. (An open-bottom drum on soil is the exception: it is usually kept full.)
SOURCES: UC MASTER GARDENERS (SACRAMENTO); CONTAINER COMPOSTING (KUMASI); “MAKING COMPOST IN A STEEL DRUM”
Common bin problems
| Problem | Likely cause | Fix |
|---|---|---|
| Smells rotten | Too wet, or too many food scraps. Too much nitrogen makes the pile putrid, acidic and compact. | Turn it and add dry browns such as leaves, sawdust or straw. |
| Flies | Food scraps left exposed, or items that shouldn’t be in there. | Bury scraps 15 to 30 cm deep, remove meat, dairy and grease, and turn. |
| Rats or mice | Exposed food, holes too large, or meat and grease inside. | Keep holes under 1.2 cm, keep the lid on, bury food and remove meat and grease. |
| Not breaking down | Too dry or too wet, too many browns, or too little nitrogen. | Add water until slightly damp, or turn if it is soggy. Add fresh greens. |
| Compacted, slimy | Filled too quickly, so air can’t get in. | Remove the top layers, add browns, and make more air holes. |
SOURCES: UC MASTER GARDENERS (SACRAMENTO); CONTAINER COMPOSTING (KUMASI)
Using your compost
Finished compost is dark, crumbly and earthy-smelling, with nothing recognisable left in it. It should be cool, not hot. Use the checks and the germination test in What is compost? and on our Trust page before you use it on seedlings.
For beds, pots and planting holes, use the same guidance as for heap compost. Mix it into the topsoil rather than leaving a thick layer on top, and keep unused compost in the shade or covered.
Questions people ask
Will it smell or attract pests in my compound?
A well-managed bin with a lid, small holes and a good mix of browns and greens should not. Smells and pests nearly always come from too many wet scraps, exposed food, or meat and grease.
Can I do this on a balcony or in a flat?
Yes, with a small closed bin. A drum may be too big. For very small spaces, bokashi or worm composting may suit you better.
Can I add cooked food?
It attracts pests, and in a plain bin it is best avoided, along with oil. Bokashi is designed to handle cooked food and leftovers.
Do I need worms?
No. Worms are for a separate method, vermicomposting. An ordinary bin relies on microbes.
What if I only have kitchen waste?
You can, but you’ll need a steady supply of dry browns, such as dry leaves, shredded paper or cardboard, to avoid a sour, wet bin.
Want help setting one up?
We train households, schools and institutions to set up and run compost bins from the waste they already produce.