A bin that fits the smallest kitchen

You do not need a garden to make compost. You need a container with a lid, a little patience, and a willingness to keep vegetable peelings out of the general waste. A sealed bin of around 100 litres — the sort sold for balconies and courtyards — will sit neatly against a wall, behind a shed door or on a small paved yard. If you live in a flat, a 15 to 20 litre lidded caddy on the kitchen counter, emptied once or twice a week into a larger bin outside, keeps smells down and fruit flies away.

The sealed design matters. Unlike an open heap, a lidded bin holds warmth, keeps rain out and stops foxes and rats from treating your kitchen scraps as a buffet. It also suits our damp, changeable climate: excess water is the enemy of a small bin, and a lid is the simplest defence against it.

Greens and browns, and why both matter

Everything in the bin is either a green or a brown. Greens are the soft, wet, nitrogen-rich things: vegetable peelings, tea leaves (split the bag if it is plastic-free; leave it out if it is not), coffee grounds, fruit cores, grass clippings, spent flowers. Browns are the dry, carbon-rich, structural things: torn cardboard, egg boxes, newspaper, loo roll tubes, dead leaves, small twigs, sawdust from untreated timber.

The classic advice is roughly two or three parts browns to one part greens by volume. In a small bin, err on the generous side with browns. A bin that smells sour or looks slimy is usually short of them.

Building the layers

Start with a five-centimetre layer of coarse browns at the bottom — crumpled cardboard or twiggy prunings — to let air and liquid move. Then add scraps in thin layers, covering each with a handful of browns as you go. Chopping peelings smaller speeds everything up, though a bin will forgive you for skipping this.

Keep a small lidded pot of torn newspaper or shredded cardboard beside the bin so the brown layer is always within reach. A sprinkle of soil or finished compost every so often introduces the microbes that do the real work.

• Do add: fruit and vegetable trimmings, tea and coffee, crushed eggshells, stale bread in small amounts, houseplant prunings.
• Leave out: cooked food, meat, fish, dairy, oils, dog and cat waste, glossy printed card, and anything treated with weedkiller.

Turning, moisture and keeping it sweet

Once a week, give the contents a turn with a small fork or a compost aerator, bringing the outside to the middle. This is the single best thing you can do in a small bin, because it restores air and stops the contents compacting into a soggy block. The ideal feel is that of a wrung-out sponge: damp, not dripping. If yours is wet, add browns and turn. If it is dry and still, add a little water and turn again.

A healthy bin smells of forest floor. Sour or ammonia notes mean too many greens; a bone-dry, inactive bin means too few. White moulds are normal and welcome. Fruit flies usually mean exposed scraps — cover them.

Small bins cool quickly in winter, so expect slower work from November to March. Insulate with an old blanket or a layer of autumn leaves, and keep adding.

When it is ready, and where it goes

Depending on the season and how often you turn it, a small sealed bin will give you usable compost in three to six months. It is ready when it is dark, crumbly and smells earthy, with only the odd eggshell or twig still recognisable. Sieve it if you like, returning the lumps to the next batch.

Use it as a top dressing for pots, mixed into your container compost, or as a mulch around borders and perennials. A thin scattering on the soil surface feeds worms and holds moisture. For pots, blend one part homemade compost with two parts bought growing medium to be safe.

Small rhythms for small spaces

The whole system thrives on routine rather than volume. Empty the kitchen caddy every few days. Turn the bin on a set day. Keep a bag of browns by the door. Two bins — one working, one maturing — mean you are never waiting for a single batch to finish before you start again.

It is a quiet, bookish sort of pleasure: a few minutes outdoors, the smell of leaf mould, a job that turns the week's tea leaves and carrot tops into something that will feed next summer's tomatoes on the windowsill. Small spaces, small bins, and a habit that pays you back in dark, crumbly handfuls.