Troubleshooting · 1 of 30
The pile will not heat
Temperature sits within 5 °C of ambient for a week or more. The material looks fine and does not smell.
01Symptom
Temperature sits within 5 °C of ambient for a week or more. The material looks fine and does not smell.
02Why it happens
In order of likelihood: the pile is too small (under 0.9 m³), too dry (under 40 % moisture), too carbon-heavy (over 50:1), or the pieces are too big for microbes to reach the interior.
03What to do
- 01 Measure the core with a stem thermometer, not your hand on the outer surface.
- 02 Squeeze a handful from the middle: if it crumbles, add water in 2 L passes with mixing between.
- 03 Add 2 kg of fresh grass or 4 L of diluted urine per cubic metre if the ratio is the problem.
- 04 Rebuild into a single larger heap rather than topping up a small one.
- 05 Chop anything above 5 cm and mix it through instead of layering it.
04Where this has come up in the logs
- batch logOak leaf and coffee chaff in a 190 L tumbler
- methodThe 18-day hot method, and why the size rule is not negotiable
- batch logSummer grass clippings balanced with corrugated cardboard
- referenceCarbon browns: the twelve materials worth knowing by number
- batch logHorse manure and straw bedding, two pallet bins
- methodWorking out C:N and moisture before the pile is built
- batch logOffice shred and delivery cardboard, 300 L insulated bin
- batch logPoultry litter and sawdust through a January cold snap
- methodCold composting: the pile that takes a year and needs almost nothing
- batch logHedge trimmings, chipped, and left for eight months
05Related logs
Every published log that touches this fault is already listed in section 04.