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Spontaneous Combustion in Cold Weather


February 17, 2021

Hi, My compost pile caught on fire this evening. I don’t know how this happened. I did know that I’m in Texas where we are having prolonged record breaking low temps. It has never been this cold here in my whole life of 41 years. We did get some snow a few days ago that has only gotten to melt very little since temps aren’t getting high enough. There hasn’t been any more precipitation except a small snow flurry for 30 minutes last night. I haven’t been able to give any moisture to it since before this storm because of frozen water pump for the water well for our neighborhood, which, thank God, they came and fixed today and we had water to help with this new unexpected crisis event in the worst year ever. Just wondering if maybe the combination of dry cold and patches of snow on the pile with little moisture could have caused dry pockets, because I’ve had my pile for a few years now with no issues at all.


Answer by JZ: Hopefully your weather changes soon.  Your question will be received by a few of my colleagues who may also respond. Here are my thoughts. Spontaneous combustion in a composting setup is rare. Your reasoning is correct, when there are pockets of dry  ingredients surrounded by by moist organics which are actively decomposing thus creating heat from the breakdown of carbohydrates may reach “flashpoint” temperatures. Compacted decomposing organics may also produce methane gas which may “flash” if surrounding temps. are high enough.

Suggest:  Aerate your pile by gently turning / churning at the same time add snow or water to moisten the whole setup.  

If there is uniform moisture, then it will be less likely to “flash”.   Hope that this is helpful.

Answer by WR: Also see Spontaneous Combustion under Composting Info in our website menu.

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