Cold Composting
Method
Cold composting is the relaxed way to make garden compost: add suitable material whenever it arises and let soil organisms do the work. It suits busy households, small gardens and mixed green waste, but patience is essential. A cold heap commonly takes a year or longer to become usable compost.
How it works
Materials break down gradually at outdoor temperatures, helped by bacteria, fungi, worms and other small creatures. Alternate moist greens, such as vegetable peelings and grass clippings, with dry browns, such as torn cardboard and dead leaves. Air and moisture matter more than precise layering: the contents should feel like a wrung-out sponge. As new material is added, the oldest compost settles at the base. Unlike a properly managed hot heap, a cold heap rarely reaches temperatures that destroy weed seeds or plant diseases.
Details
Use a lidded compost bin or a contained heap on bare soil, where worms can enter and excess water can drain. Keep a small store of shredded cardboard, paper or leaves beside the bin so every kitchen caddyful can be covered. Chop tough stems and woody prunings before adding them, or compost them separately for longer. Do not add meat, fish, dairy, cooked food or dog and cat waste, as these can attract vermin; some council garden-waste collections accept different materials. Empty finished compost from the bottom in spring or autumn, then return unfinished pieces to the bin.
Tips
Keep the lid on during prolonged rain and add extra browns after a lawn cut. Turn the contents once or twice a year if convenient, but cold composting still works without regular turning. Avoid compost made from manure, hay or grass where aminopyralid weedkiller residues are suspected, as they can harm tomatoes, beans and potatoes.
Cold Composting: frequently asked questions
How does cold composting work?
Materials break down gradually at outdoor temperatures, helped by bacteria, fungi, worms and other small creatures.
What do I need to know about cold composting?
Use a lidded compost bin or a contained heap on bare soil, where worms can enter and excess water can drain.
What are some tips for cold composting?
Keep the lid on during prolonged rain and add extra browns after a lawn cut.
General guidance for UK gardens and allotments. Page updated 18 Sep 2026.