A bin that earns its footprint

Even a modest plot — a courtyard, a back yard, a couple of raised beds — produces enough peelings, tea leaves and grass clippings to fill a compost bin over the course of a year. What you get back is dark, crumbly material that holds water, feeds soil life and saves you buying bagged improver. It also keeps food waste out of the bin lorry, where it would break down without oxygen and release methane instead.

The good news is that a compost bin is the least demanding thing in the garden. It asks for scraps, a bit of balance and occasional attention. Get those right and you will never need to buy a grow-bag again.

Choose a bin that suits your space

The classic is the plastic "dalek" bin, usually available at a discount through your local council. It holds between 220 and 330 litres, needs roughly a square metre of ground, and works best sitting directly on bare soil so that worms, woodlice and microbes can move in from below. If you have only paving, lift the base plate or leave the hatch open to the ground and turn the contents more often.

For tighter spots, a tumbler takes up little room and makes turning effortless, though it needs filling in one go rather than a handful at a time. A wormery suits a patio or balcony and takes kitchen scraps only — no grass clippings, no branches. A bokashi bin ferments cooked food, meat and fish indoors, but what comes out is not compost; it must be buried in a trench or added to a heap to finish.

Two parts brown to one part green

Balance is the whole game. Composting microbes need nitrogen for energy and carbon for structure, and the trick is remembering which of your scraps supplies which.

• Greens — wet and nitrogen-rich: vegetable peelings, fruit scraps and cores, tea leaves, coffee grounds, grass clippings, spent cut flowers, annual weeds before they seed.
• Browns — dry and carbon-rich: shredded cardboard and plain paper, egg boxes, loo roll tubes, autumn leaves, straw, woodchip, sawdust from untreated timber.

Layer them as you go, aiming for roughly two parts brown to one part green by volume. In practice that means a couple of handfuls of torn cardboard or a small bucket of leaves for every caddy-load of peelings. Get the ratio right and the heap smells faintly of woodland after rain. Let greens take over and you will know about it within a week.

What to leave out

A cold domestic heap will not break down everything, and a few things cause more trouble than they are worth.

• Cooked food, meat, fish, dairy and cooking oils — these attract rats, foxes and wasps.
• Perennial weeds such as couch grass, bindweed and dandelion roots, plus anything carrying seeds.
• Diseased plant material, particularly brassica roots and anything with clubroot.
• Glossy magazines, coated cartons and receipts — they do not rot and can carry plastic coatings.
• Pet waste, cat litter and nappies.

Many tea bags still contain a plastic mesh that will survive the heap for years; tear the bag open and compost only the leaves. Compostable caddy liners are fine if they carry the right certification, but they break down slowly, so tear them in first.

Moisture, air and a bit of turning

Aim for the texture of a wrung-out sponge. Squeeze a handful: a drop or two of moisture is perfect, a trickle means it is too wet and needs browns and a good mix, and a dry crumble means it needs water and more greens. Keep the lid on to hold moisture in, but open the hatch now and then for airflow.

Turning is the single thing that speeds everything up. Fork the contents from the bottom hatch into a second bin, or use an aerating tool pushed in and twisted, every three or four weeks through the summer. A well-built heap will reach 40 to 60°C in the middle, hot enough to kill many weed seeds and speed up the whole process. If yours never heats, it is usually short of greens or short of volume — a full bin works far better than a half-empty one.

When it is ready, and sharing the load

Expect six to twelve months for a dalek bin, faster if you turn it regularly and add plenty of shredded cardboard. Finished compost is dark, crumbly and smells earthy, with no recognisable scraps left. Sift out any lumps and return them to the next heap. Use it as a mulch around shrubs, fork it into beds, or sieve it for potting mixes.

If a bin will not fit, you are not out of options. Sharing one with a neighbour halves the effort and doubles the input. Allotment sites and community gardens often welcome kitchen scraps, and many councils now run weekly food waste collections, which at least keeps peelings out of landfill. Whatever you choose, keep a small lidded caddy by the sink, empty it every couple of days, and add a layer of browns each time. Small habits, repeated, are what turn a few potato skins into next year's soil.