Troubleshooting · 17 of 30
Finished compost reads pH below 6
A pH meter reading of 5.2-5.9 in finished compost, and poor germination when it is used in a seed mix.
01Symptom
A pH meter reading of 5.2-5.9 in finished compost, and poor germination when it is used in a seed mix.
02Why it happens
A feedstock dominated by fruit waste, coffee grounds or pine needles, and a pile that never exceeded 40 °C, so the organic acids were never broken down.
03What to do
- 01 Add 1 kg of wood ash or ground eggshell per cubic metre and re-mix.
- 02 Take a second pH reading after three weeks before using the compost.
- 03 Run the next batch hotter — organic acids break down fastest above 55 °C.
- 04 Do not add ash to a pile that already smells of ammonia.
04Where this has come up in the logs
No published log has hit this one yet. The sequence above is the standard order at this bench.