How do I compost when there is no room for a heap?

Small-space composting fails for a specific reason: a small bin cannot heat up, so people judge it by the standard of a hot heap and conclude it does not work. It does work. It just works cold and slowly, and the sensible approach is to pick a system whose output you actually want rather than to fight the physics.

Safety

What you'll need

• Whichever system you choose
• A lidded kitchen caddy
• Spade for trench composting (optional)
• Torn cardboard as a brown source (optional)

Step by step

1. Try trench composting first — it needs no equipment.Dig a trench a spade deep in a bed or between rows, tip raw kitchen waste in as it arrives, cover with 150mm of soil, and move along. It composts in place and beans, peas, courgettes and squash planted over it the following season do particularly well.
2. Consider a wormery for a balcony or a yard.It is compact, produces very fine compost and a strong liquid feed, and does not smell if it is running properly. It takes raw fruit and vegetable waste, and dislikes large amounts of citrus, onion and anything cooked.
3. Use bokashi for cooked waste.A sealed bucket fits under a sink and ferments everything including meat and dairy. The output still has to be buried in soil or added to a heap, so it works best paired with a bed, a large tub or a neighbour's heap.
4. Buy an insulated hot composter if the budget allows.These are the only genuinely small containers that heat, because they are insulated rather than large. They take cooked food, they are sealed against rats, and they produce compost in weeks rather than years.
5. Accept cold composting in a dalek bin.A standard cone bin in a small garden makes perfectly good compost in twelve to eighteen months. It never gets hot, so keep perennial weed roots, seeding weeds and diseased material out of it.
6. Solve the browns problem deliberately.Small gardens generate almost no dry brown material, which is why small bins go slimy. Keep a bag of torn cardboard and egg boxes beside the bin and add a handful with every bucket of kitchen waste.
7. Compost leaves separately if you have a tree nearby.A bin bag with a few holes punched in it, filled with damp leaves and left behind the shed for a year, makes leaf mould with no space and no effort.
8. Use the council food waste collection for the overflow.Most UK councils collect food waste and process it at temperatures no home system reaches. There is no failure in using it for bones, cooked food and the surplus a small system cannot absorb.
9. Site the system for the winter, not the summer.The bin you have to cross a wet dark garden to reach in January is the bin that stops being used. Near the back door beats the far corner every time.

Tips

• Trench composting is the most underused method there is: no bin, no turning, no smell, and the crop over it is visibly better.
• A wormery on a balcony must be shaded in summer and insulated or moved somewhere frost-free in winter — worms die at both extremes.
• Two small bins beat one large one in a small garden, because you can leave one to finish.

Common mistakes

• Expecting a small bin to get hot — Below roughly a cubic metre a heap cannot insulate itself, so it composts cold. That is fine — it just means twelve months rather than three, and no weed seed or pathogen kill.
• Filling a small bin with kitchen waste only — With no garden waste to balance it, it becomes a sour wet sludge. Cardboard is the substitute and it needs adding constantly.
• Putting a wormery in full sun — The worms cook. A wormery wants shade in summer and shelter in winter.

Alternatives

• Trench composting: No container, no cost, no turning. Raw waste buried a spade deep in a bed. Needs bare ground and a bit of patience.
• Wormery: Compact and suits a balcony. Excellent fine compost and liquid feed. Raw plant waste only, and needs protecting from heat and frost.
• Bokashi: Sealed bucket, takes cooked food, fits indoors. Output must be buried in soil or added to a heap afterwards.
• Insulated hot composter: The only genuinely small bin that heats. Takes cooked food, rat-resistant, fast. The expensive option.
• Standard cone bin: Cheap and simple. Cold, slow compost in twelve to eighteen months. Keep perennial weeds and disease out.

Questions people ask