Hot Composting
Method
Hot composting makes usable garden compost quickly by building a generous, well-balanced heap in one go. It is ideal when an allotment or large garden produces plenty of material at once. A successful heap heats strongly, needs attention, and can produce compost within a few months rather than a year.
How it works
A heap of roughly 1 m by 1 m or larger holds enough warmth for microbes to multiply rapidly. Mix roughly equal volumes of greens and browns, aiming for moist but open material rather than dense clumps. Microbial activity raises the temperature, speeding decomposition and helping to destroy many weed seeds and plant pathogens. Check the centre after several days, then turn the heap when it cools, moving the outer material inward. Rebuild it with water if dry or browns if wet, repeating the heating cycle as material breaks down.
Details
Gather materials before starting so the heap can be made in one session. Good combinations include shredded prunings, autumn leaves, cardboard, grass clippings, vegetable peelings and spent annual plants. A wooden slatted bay or insulated compost bin makes turning easier. Keep out meat, fish, dairy, cooked food and dog or cat waste because they attract vermin; bokashi and some council schemes have different rules. Use a compost thermometer if you enjoy monitoring, but warmth, steam and a rapid reduction in volume are useful signs. Break up compacted grass layers while turning.
Tips
Wear gloves when turning and cover a new heap with a breathable cover or old compost sack in heavy rain. Do not rely on heat alone to make diseased material safe if you cannot achieve a sustained hot core. Avoid inputs containing suspected aminopyralid residues, particularly manure, hay and grass, before using compost near tomatoes, beans or potatoes.
Hot Composting: frequently asked questions
How does hot composting work?
A heap of roughly 1 m by 1 m or larger holds enough warmth for microbes to multiply rapidly.
What do I need to know about hot composting?
Gather materials before starting so the heap can be made in one session.
What are some tips for hot composting?
Wear gloves when turning and cover a new heap with a breathable cover or old compost sack in heavy rain.
General guidance for UK gardens and allotments. Page updated 19 Sep 2026.