Starting a Compost Heap in a Small Garden

Why a small garden is no excuse

There is a stubborn myth that composting belongs to the people with half an acre and a rusty Land Rover. In truth, the smaller the garden, the more you feel the benefit. A modest plot in a terraced street generates roughly the same weight of kitchen peelings as a large one, and it has nowhere near enough soil to absorb them. A compost heap turns that waste into something genuinely useful: a crumbly, sweet-smelling material that feeds your borders, holds moisture in pots and saves you a fortune in bagged compost.

You do not need a three-bay wooden system or a pitchfork the height of a garden fork. A single bin of around 200 litres, tucked behind a shed or beside a water butt, will quietly process most of what a household of two to four people produces. The trick is understanding what the heap is actually doing, and giving it the three things it wants: air, moisture and a sensible mix.

Choosing a spot and a bin

Site the bin on bare soil if you possibly can, not on paving. Worms and soil microbes will travel up from below to lend a hand, and excess liquid can drain away rather than pooling. Partial shade is ideal — full sun dries a heap out and a north-facing wall keeps it cold and sluggish. Leave enough room to get a fork in and to turn the contents out onto a sheet when the time comes.

For a small garden, the practical options are:

• A dalek-style plastic bin — cheap, neat, and available from most councils at a discount. Remove the little hatch door at the base to dig out finished compost.
• A tumbling bin — good for small courtyards, though it holds less than it appears to and needs filling in one go to work well.
• A homemade bay of pallets or scrap timber — cheap and excellent, but allow 1 metre square, which is a lot of a tiny garden.
• A wormery — brilliant for kitchens with no garden at all, though it handles cooked food and scraps rather than prunings.

Greens and browns: the balance that does the work

Every heap is a tug of war between two camps. Greens are soft, wet and nitrogen-rich: vegetable peelings, fruit scraps, used tea leaves and coffee grounds, grass clippings, spent annuals, bolted lettuces. Browns are dry, woody and carbon-rich: cardboard, egg boxes, toilet roll tubes, torn-up paper, prunings, autumn leaves, straw, and sawdust from untreated timber.

Get the ratio roughly right and the heap heats up, smells faintly of woodland and breaks down quickly. Get it wrong and you will know about it. Too many greens and you get a slimy, ammonia-smelling swamp. Too many browns and nothing happens for months.

Aim for something close to two parts browns to one part greens by volume — roughly a bucket of torn cardboard for every half-bucket of peelings. Cardboard is the small gardener's secret weapon. Corrugated stuff tears easily, soaks up surplus moisture and adds structure that lets air move through the pile. Always remove the tape and any glossy labels.

Building the heap in layers

Start with a 10cm bed of coarse browns — twiggy prunings, scrunched cardboard — to keep the base aerated and stop the whole thing turning into a soggy mat. Then add your materials in thin alternating layers rather than dumping a week's worth of peelings in one lump. A layer of kitchen scraps, a layer of torn cardboard, a sprinkle of soil or old compost, then repeat.

That sprinkle of soil matters more than people realise. It introduces the bacteria and fungi that do the actual work, and it stops the layers compacting. If you have a few comfrey leaves or nettles going spare, add them — they act as an activator and speed everything along. Chop anything bulky with a spade or secateurs as you go. The smaller the pieces, the faster the result.

Turning, moisture and reading the heap

Air is the difference between composting and rotting. Once a fortnight through spring and summer, plunge a fork into the heap and turn it over, bringing the outside to the middle and the middle to the edges. A tumbling bin just needs a few rotations. This is also the moment to check moisture.

The squeeze test tells you everything. Grab a handful from the middle and squeeze. It should feel like a wrung-out sponge — damp, not dripping. If it is sodden, add cardboard and turn it. If it is dusty and dry, water it with a can and turn it. In a wet British winter, a lid or an old piece of carpet over the top keeps the rain out, and in a hot July you may need to water it once a week.

Signs you are on track: the heap shrinks noticeably, feels warm in the middle, and hosts a few worms and woodlice. Signs to fix: fruit flies (bury scraps deeper), a sour smell (more browns, more air), or a heap that simply sits there doing nothing (too dry, too woody, or too cold).

What to leave out, and when it is ready

Keep meat, fish, dairy, cooked leftovers, dog and cat waste, and diseased plant material out of the bin. They attract rats and smell unpleasant in a small space, and a domestic heap rarely gets hot enough to kill pathogens. Perennial weeds such as bindweed, ground elder and dock should also stay out, along with anything seeding — you will simply be sowing them back into your borders later.

Depending on the season and how often you turn it, a small heap takes anywhere from three months to a year. It is ready when it looks like dark, crumbly cake, smells earthy rather than sour, and you cannot recognise what went in. Dig out the bottom hatch, sieve out any stubborn lumps and return them to the next heap. Everything else can be forked through your beds, mixed into potting compost or used as a mulch. From a bin the size of a wheelie, a small garden can produce two or three bags a year — a quietly generous return on very little effort.