Composting for Beginners: How to Make Good Compost Without Overthinking It

Compost is the closest thing gardening has to free money. It improves drainage in clay and water retention in sand, feeds soil life, and replaces most of what you would otherwise buy in bags. And the process is genuinely hard to break — organic matter rots whether you help or not. All you are really doing is deciding whether it takes three months or two years, and whether it smells.

The short answer

Aim for roughly two-thirds dry browns (cardboard, dead leaves, straw) to one-third wet greens (kitchen scraps, grass, fresh weeds) by volume, keep it as damp as a wrung-out sponge, chop anything thicker than a pencil, and turn it every month or so. If it smells, add browns and air. If nothing is happening, add greens and water.

Browns and greens, and why the ratio is the whole game#

Composting microbes need carbon for energy and nitrogen to build cells. Get the balance roughly right and they multiply, heat the heap and work fast. Get it wrong and you either starve them or drown them.

The single most common failure is a bin filled entirely with kitchen scraps and grass. That is 100% greens. It becomes a sour, airless sludge within a fortnight. Keeping a bag of torn-up cardboard next to the bin and throwing in a couple of handfuls every time you add food waste fixes it permanently.

What to put in#

Yes, freely:

• Vegetable and fruit peelings, cores, skins
• Coffee grounds, paper filters, tea leaves (check tea bags — many contain plastic)
• Crushed eggshells (slow, but they do go)
• Grass clippings, in thin layers mixed with browns
• Soft prunings and spent annual plants
• Dead leaves, in quantity — or stack them separately for leaf mould
• Cardboard, paper, egg boxes, toilet roll tubes
• Straw, hay, woodchip, sawdust from untreated timber
• Animal bedding from herbivores — rabbits, guinea pigs, chickens

No, or with real caution:

• Meat, fish, dairy, cooked food — rots fine, attracts vermin reliably. Use a sealed hot composter, bokashi, or the council food collection.
• Dog and cat faeces — pathogen risk that a cool heap will not reach the temperature to kill.
• Perennial weed roots — bindweed, couch grass, ground elder, horsetail. These survive and spread. Drown them in a bucket for a month first.
• Diseased plant material — clubroot, blight, honey fungus and white rot all persist. Bin these.
• Glossy or laminated paper — the coating does not break down.
• Treated or painted timber, and its sawdust — you do not want those preservatives in your beds.
• Anything labelled compostable that is actually plastic — most compostable packaging needs industrial temperatures and will still be there next year.

Cool heap or hot heap#

There are two workable approaches, and the difference is entirely about whether you build all at once.

Cool composting is what most people do: add material as it arises, over months. It works, it needs almost no effort, and it takes six to twelve months. It never gets hot enough to kill weed seeds or pathogens, so be selective about what goes in.

Hot composting means gathering a large volume of material — at least a cubic metre — mixing it properly, and building the whole heap in one go. It will reach 55–65°C within days, kill most weed seeds and pathogens, and finish in six to eight weeks if you turn it weekly. It is more work and needs you to stockpile material, but it is dramatically faster.

Most gardens end up doing cool composting for kitchen waste and hot composting once or twice a year when there is a big clear-up.

Troubleshooting#

Which bin#

The bin matters much less than the ratio, but it does affect how pleasant the job is.

• Plastic cone bins — cheap, often subsidised by councils, fine for kitchen waste. Awkward to turn, so expect the slow route.
• Three pallets in a square — free, excellent airflow, easy to fork and turn. The volume also helps it heat up. Best value of anything here.
• Tumblers — turning is effortless and they are rodent-proof, which is their real selling point. Capacity is small and you need a second one, because you cannot add fresh material to a batch that is nearly finished.
• Hot bins (insulated) — expensive, but they will take cooked food and small quantities of meat, and they work through winter. Worth it if you have no council food collection.
• Wormeries — brilliant for kitchen waste in a flat or small courtyard, and the liquid feed is excellent. They cannot handle garden waste volume.

Using it#

Finished compost is dark brown, crumbly, and smells like a woodland floor. You will not identify what went into it.

• As a mulch — spread 2 inches on the surface of beds in autumn or spring. This is the highest-value use, and it is exactly what the no-dig method in our vegetable garden guide is built on.
• As a soil improver — fork it lightly into planting holes and containers.
• Not as seed compost — home compost is too rich and too variable in texture for seed sowing, and often carries weed seeds. Buy seed compost for that.

Sieve out anything unrotted — twigs, avocado stones, the odd corn cob — and throw it back in to seed the next batch with active microbes.

Where to go from here#

Compost is the input for almost everything else. If you are building beds, our raised bed layout ideas covers how much compost a bed actually takes and how to fill one without buying a mountain of bagged product. And if you are turning heaps regularly, a decent fork matters more than you might think — see gardening tools for beginners.