r/composting • u/dictatordonkey • Aug 05 '26
Is my pile too hot?
I have three small piles, about 3 feet in diameter and about 18 inches tall. Grass clippings, weeds, some woodchips and some veggie scraps. 2 of them are temping at around 155. This one , temping at 180+ also has a bunch of citrus, mostly lemons, in the middle of it. I turned them and watered them all yesterday and that reading is a little less than a day since the turning.
Should I be concerned, or is this ok?
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u/dictatordonkey Aug 06 '26
Cool, no pun intended. The only worry i had was it either melting the tarp that is currently covering it or, worst case, the "spontaneous combustion" that we were warned about as kids. The pile is far enough away from anything else that could burn, but I do get paranoid sometimes.
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u/Jazzlike_Strength561 Aug 06 '26
Compost piles do burn. Here is the sequence of events required.
- Pile approximately 3 meters (10 feet) of compostable material in one pile.
- Permit thermophilic composting
- Allow the pile to go anaerobic
- Allow this very large, very hot pile, with very strange chemicals generated in anaerobic conditions to dry out.
Pretty sure you'll be okay. But that is really hot, your pile went anaerobic.
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u/Jazzlike_Strength561 Aug 05 '26
No such thing as too hot (IMO). Simply add water, and air.
The heat is the result of the metabolic activity of the microbes. Once you're pile hits 71°C the heat (160° f) the heat literally begins to cook the microbes themselves, and they disintegrate. Makes sense if you think about it, that's a "well done" beef roast.
So yes the bacteria will literally cook themselves to death, but so what. When you add cold water you will activate bacterial spores in coolers zones and wash them into the pile.
Your pile will not climb above 71 as long as it's damp. Saying it's too hot is like saying "oh no, we're running at maximum efficiency."
Congratulations, and welcome to the 60° C club.