Composting Basics for Small UK Gardens

Why a small garden still deserves a compost heap

If your outdoor space is a courtyard, a narrow side return or a postage-stamp lawn behind a terrace, composting can feel like something other people do with acres to spare. In truth, a single 220-litre bin takes up less ground than a wheelie bin, and it will quietly turn your tea leaves and torn cardboard into the richest thing you can put on your beds. You send less to landfill, buy less bagged compost, and gain a heap that warms up like a living thing through the summer. The only real requirements are a little space, a little patience and a rough sense of balance.

Done well, home compost is dark, crumbly and smells of woodland floor rather than rubbish. Done badly, it turns slimy and sour, which is usually a sign that something simple needs adjusting.

Pick a bin that suits a tight space

You do not need a three-bay wooden system. For most small UK gardens, one good container is plenty:

• Dalek-style bin: 220 to 330 litres, cheap, lidded and rodent-resistant. Stand it on bare soil or paving, not on decking, so worms and drainage can do their work.
• Wooden slatted bin: 1 metre square is generous; even 60cm works. Slats let air in, which keeps the heap sweet. Line the sides with cardboard if it dries out too fast.
• Wormery: ideal for courtyards and balconies. Worms process kitchen scraps only, and the liquid drained off makes a superb feed diluted 1 part to 10 in a watering can.
• Bokashi bucket: a sealed indoor fermenter for flats with no outside space at all. You bury the fermented waste afterwards or add it to a bin.

Site it in half-shade near the kitchen door, so you actually use it in the rain. A little autumn sun helps, but all-day baking dries a heap out fast.

Get the green and brown balance right

Aim for roughly two to three parts brown material to one part green, by volume. Greens are wet and nitrogen-rich; browns are dry and carbon-rich. Too many greens and you get a smelly sludge. Too many browns and nothing happens for months.

• Greens: vegetable peelings, fruit scraps, tea leaves, coffee grounds, grass clippings in thin layers, spent bedding plants, annual weeds before they set seed, cut flowers.
• Browns: torn cardboard, loo roll tubes, egg boxes, newspaper, shredded paper, dead leaves, straw, a little woodchip, the cardboard sleeves from ready meals.

Keep out cooked food, meat, fish, dairy, oils, diseased plants, perennial weed roots such as bindweed and dock, pet waste, glossy magazines and plastic-lined tea bags. Chop anything bulky with shears — smaller pieces break down far faster, which matters when your heap is the size of a doormat.

Turn, water and keep it warm

Air is what separates composting from rotting. Every two to four weeks from spring to early autumn, fork the outside of the heap into the middle and the middle out to the edges. A compost aerator or a strong broom handle pushed in and twisted does the job in a dalek bin without lifting the lid for long. In winter, leave it alone; cold slows everything down and turning only loses what heat you have.

Moisture should feel like a wrung-out sponge. If it is dusty and dry, water it with a can and add fresh greens. If it is sodden, stir in shredded cardboard and turn it. A well-built heap can reach 60°C in the core within a week, which kills many weed seeds and speeds everything up.

Fixing the usual problems

• Slimy and smelly: too wet and too green. Add browns, turn thoroughly, leave the lid off for a day.
• Bone dry and inert: add water and greens, then turn.
• Fruit flies: bury kitchen scraps in the centre rather than tipping them on top.
• Mice or rats: stop adding cooked food, keep the lid secure, and stand the bin on wire mesh.
• Slow going: be patient in winter. Most active composting in the UK happens between May and September.

When it is ready, and how to use it

Depending on the season, expect usable compost in six to twelve months, or as little as three or four if you turn regularly. It is ready when it is dark, crumbly, free of recognisable peelings, and smells sweet and earthy. Sieve out any stubborn twigs and put them back in the next heap.

Use it as a mulch around shrubs, fork it into vegetable beds, or mix it with grit and loam for potting. Even a modest bin will give you a bucket or two a year, and that is enough to transform a small border. Start with one bin, get the balance roughly right, and let the worms do the rest.