Starting a compost pile takes about an afternoon and almost no money. The short version: pick a spot or a bin, add roughly three parts “browns” (dry leaves, cardboard, paper) to one part “greens” (food scraps, grass clippings) by volume, keep it about as damp as a wrung-out sponge, and turn it every week or two. In three to six months, the bottom of the pile becomes dark, crumbly compost. The rest of this guide covers the decisions that trip beginners up — which bin, what’s safe to add, and how to fix a pile that smells.
Why bother composting?
Food scraps and yard waste together make up more than 30 percent of what US households throw away, according to the US EPA. In a landfill, buried food waste breaks down without oxygen and produces methane. In a compost pile, the same material breaks down aerobically and turns into a soil amendment that improves water retention and feeds soil life. If you garden at all, compost replaces bagged soil conditioner you’d otherwise buy.
Step 1: Choose your composting setup
There’s no best system — only the best match for your space and how much effort you want to put in.
| Setup | Cost | Space needed | Effort | Time to compost |
|---|---|---|---|---|
| Open pile | Free | 1 m² / 10 sq ft of yard | Low | 6–12 months |
| Wire or pallet bin | $0–40 | 1 m² / 10 sq ft | Low | 6–12 months |
| Plastic “dalek” bin | $50–100 | 0.5 m² / 5 sq ft | Low | 4–8 months |
| Tumbler | $100–250 | 1 m² / 10 sq ft | Medium | 2–3 months |
| Worm bin (indoors ok) | $30–150 | Under a sink | Medium | 2–4 months |
| Bokashi bucket (indoors) | $40–80 | A corner of the kitchen | Medium | 4–6 weeks to pre-compost |
If you have any outdoor space, start with a simple bin or pile — it’s the most forgiving. If you’re in an apartment, a worm bin or bokashi bucket works; see our indoor composting guide once it’s live.
Step 2: Get the browns-to-greens ratio roughly right
Compost microbes need carbon (“browns”) and nitrogen (“greens”) in balance. The science says a carbon-to-nitrogen ratio around 25–30:1 is ideal (Cornell Waste Management Institute), but you don’t need to calculate anything. The practical rule that works: two to three buckets of browns for every bucket of greens, by volume.
Browns (carbon): dry leaves, shredded cardboard, paper, straw, wood chips, sawdust from untreated wood, paper egg cartons.
Greens (nitrogen): fruit and vegetable scraps, coffee grounds, tea leaves, fresh grass clippings, plant trimmings, crushed eggshells (technically neutral, but they add calcium).
Most beginners’ problem is too many greens — a slimy, smelly pile — because kitchen scraps arrive daily and browns don’t. The fix: keep a bag of shredded cardboard or autumn leaves next to the bin, and cover every food-scrap deposit with a double handful of browns.
What should you not put in a compost bin?
Leave these out of a standard home pile:
- Meat, fish, dairy, and cooked food with fat — they compost, but slowly, and they attract rodents. (Bokashi systems handle them; open piles shouldn’t.)
- Oily or greasy anything — coats material and slows aerobic breakdown.
- Diseased plants and weeds with mature seeds — home piles often don’t get hot enough to kill either.
- Dog and cat waste — pathogen risk in compost destined for food gardens.
- Glossy or plastic-coated paper, and anything labelled “compostable plastic” — most need industrial facilities, not a backyard pile (NRDC).
- Treated or painted wood in any form.
Step 3: Build the pile
- Put the bin bare on soil if you can — worms and microbes migrate in from below. On concrete, add a few shovelfuls of garden soil to inoculate it.
- Start with a 10–15 cm (4–6 in) layer of coarse browns — twigs or wood chips — for airflow at the base.
- Alternate layers: a bucket of greens, covered by two to three of browns.
- Dampen as you go. Target the feel of a wrung-out sponge — moist, never dripping. In dry climates, water the pile occasionally; in wet ones, cover it.
How often should you turn compost?
Every one to two weeks with a garden fork, if you want compost in months rather than a year. Turning mixes oxygen in, which keeps the aerobic microbes working and the temperature up. A well-fed, turned pile heats to 54–65°C (130–150°F) in the middle — hot enough to speed decomposition and kill most weed seeds. If you don’t turn it at all, everything still composts; it just takes 6–12 months and the outer layer lags behind the core (RHS).
How do you know when compost is ready?
Finished compost is dark brown, crumbly, smells like forest soil, and you can no longer identify what went in — apart from the odd avocado stone or corn cob, which you just toss back in. Typical timelines: 2–3 months for a turned tumbler in summer, 4–6 months for a maintained bin, up to a year for a neglected pile. Use it as a 5 cm (2 in) top-dressing on beds, mixed into planting holes, or sieved into potting mix.
Troubleshooting: smells, pests, and a pile that does nothing
It smells like rot or ammonia. Too many greens or too wet. Turn it and mix in a generous load of shredded cardboard or dry leaves. Smell gone in days.
Rats or raccoons are visiting. Stop adding meat/cooked food if you were, switch to a closed bin with a lid and a base plate, and bury fresh scraps in the centre of the pile rather than leaving them on top.
Nothing is happening. Usually too dry or too brown. Water it, add a nitrogen kick (grass clippings or coffee grounds), and turn. A pile that’s too small also stalls — aim for at least 1 m³ (a cubic yard) for a hot pile; smaller volumes still work, just cold and slow.
Ants everywhere. The pile is too dry. Moisten and turn.
The habit that makes it stick
Composting fails in kitchens, not in bins. Keep a small lidded caddy on the counter for scraps and empty it every day or two — the walk to the bin is the whole system. Pair each caddy trip with a browns top-up, and the ratio takes care of itself.
Once your first batch is underway, the next upgrades are a DIY compost bin sized to your garden’s actual output, or a worm farm if you want faster castings for containers — guides on both are on the way.