I'm reasonably good at building compost heaps - they don't smell, the end product is dynamite for the garden, and they are chock full of worms. But, my compost heap is not heating up any more, not even when I add new material. I compost EVERYTHING except humanure (I'd do that too, but there is no space in my bathroom to keep the buckets). I probably add four to six gallons of material every week, mostly kitchen scraps, and in the year or so since I built the heap, the new material has always heated up within a few days, usually to about 45degrees celsius. For the last month or two, the new material has only heated about five degrees above the background temp of the heap. Here are my theories, would appreciate your feedback:
#1 - too many worms. The heap is incredibly full of compost worms - could they be eating the newly added materials before they have time to heat up? A lot of the stuff I add has started to decompose so I imagine it looks like heaven to the wriggly beasts.
2# - it's winter. It is a big heap, more than a cubic meter, so should have enough mass to self-insulate, but maybe not. However, it was winter when I originally built the heap, and it got as hot as 66 degrees Celsius, so would surprise me if the outside temp is the problem.
3# - lower layers are quite compacted. The bottom thirty centimetres or so is quite compacted and much damper than the rest of the heap - could that be sucking heat away from the top parts of the heap?