compost pile catch fire??

[mtgarden gal]

Ive just started my first compost pile. It's still really small. I was reading thru past posts on this forum subject and read an entry that suggested a compost pile could catch fire. Is this true??
If this is true, now I'm afraid to put this pile anywhere near my house, which would be hard to do since I live in town and was going to put the compost pile in my backyard.

[greenstubbs]

It can smolder alot if the conditions are right and it's dry, but if it has been watered it really won't catch fire. If your thinking that it's going to burst into a bonfire, it won't do that. Just keep it in a sunny area away from the house and you'll be fine.

[tomc]

I suppose anything is possible. I've gotten a pile hot enough to steam in the fall.

With enough urea and a little bit of deisel fuel, its possible to blow up a federal building...

With yard waste, and some manure, I've never managed to get a pile hot enough to catch fire. After 35 years of trying, I'm not so sure I'm gonna succeed.

[rainbowgardener]

Yeah, I have trouble even getting mine to heat up as much as it is supposed to. You would have to work REALLY REALLY hard to try to get a compost pile that had exactly the right balance of greens and browns to heat up really well, enough moisture to keep it cooking, but not enough to cool it down, turning it enough to aerate it, but not enough to disrupt the hot parts, to try to get one to burn, and even then it probably wouldn't work. The most I've ever seen in many years of doing this is steaming.

[john gault]

I think the chances are very remote, but I suppose it's possible if all the conditions are right. What causes these spontaneous-type fires are more of a concern for hay storage, because of the conditions, but the principle is the same. Interesting reading: https://www.aces.edu/dept/forages/hay/hayfires.html ;;; https://www.discoverhorses.com/preventing-barn-fires.html

BTW, for this to happen, not only would you need to right conditions, you'd also need to let the pile sit there undisturbed for some time; once you turn the pile the clock starts all over again, provided the conditions are still there.

[Gary350]

The wet stuff in the compost is what generates the heat. The more wet you have the better it works.

When farmers bale hay they let the cut grass lay in the sun until it is very dry. If you bale the hay with too much moisture it generates heat and it can burn a barn down. My Grandfather use to feel the hay, break the pieces to see if they would snap or bend, roll it between his fingers. When it was satisified it was dry enough then he would bale it. My Grandfather use to watch the weather forecast he said that he needed 5 full days of sun to bale hay.

I have seen baled hay laying in a field smoking.

[mtgarden gal]

phew, ok thanks everyone, that puts my mind at ease. I was about to start having nightmares about my house catching fire due to my cooking poopoo pile outside.

[toxcrusadr]

You could not make a pile catch fire if you try, it is so rare and conditions have to be juuuust right. It's like getting struck by lightning - yes it can happen but how many people do you know...

BTW a pile has to be at least a cubic yard to generate and keep that much heat inside in the first place. Usually the big industrial piles are what catch fire. And even then it's a smoldering thing.

Good idea not to put the pile right up against the house anyway, for lots of reasons.

[mtgarden gal]

out of curiousity, what are the reasons not to put the pile next to the house? (I'm sure they are obvious, but the obvious is not always obvious to me....)

[toxcrusadr]

1) Although compost is generally odorless if properly managed, you can't guarantee your pile will never have an ill wind, and you don't want that coming right into the kitchen window.

2) The compost pile is a living thing and has not only bacteria but various beneficial insects that are part of nature's cleanup crew. They are free spirits, though, and may not always stay in the immediate confines of the bin.

Those are the big ones that I can think of right off. Not to suggest a compost pile is a smelly insect ridden disaster - it is not, or we would not have forums where scores of people are doing it and talking about it. :-] It is just prudent to be, well, prudent.

[rainbowgardener]

Pile needs to stay damp, and keeping something damp up against your house all the time probably not too good for it. Compost pile can harbor cockroaches (I know, people go eew, but that is where they belong, they are detritovores and part of the process of breaking stuff down) and sometimes even termites and other critters. Mice and shrews come to my pile sometimes, though they don't live there. None of that is a problem, but probably not a good thing next to your house. Put the compost pile at the other end of the garden and draw all that stuff away from your house.

[mtgarden gal]

thanks!

[toxcrusadr]

Rainbow is right about all those critters, but don't be deterred by them. They just do their thing in there and that's where the magic comes from.

At my office we compost all our coffee grounds, food scraps etc. The large pallet 'finishing' bin that gets the partially-composted stuff out of the black plastic bins twice a year, has a plastic tarp cover to manage the moisture. Sometimes, in spring, keeping warm under that tarp, we find a harmless but large black snake, waiting for a mouse lunch. We don't bother him and he doesn't bother us. I don't advertise that to *all* the volunteers, though. They don't use that particular bin and don't need to know.

Bottom line, all these guys are around your yard anyway, you just don't see them. I've seen a cat catch mice in the most manicured, Better Homes and Gardens suburban lawn you have ever seen. They're out there.

[imafan26]

Yep they can catch fire, but it is not common for a home pile to have a serious problem. You could get your pile hot enough to cook and egg though.

The commercial composter here Hawaiian earth products have had several spontaneous combustion fires at their facility. A large enough burn for the fire department to come out.
They are in one of the hottest areas on Oahu and they have a hard time getting enough water on the piles especially in summer.

The fire department said their piles were too high and that caused the heat to build up.

[mtgarden gal]

Thanks, Imafan26

It's off topic, but I was wondering about gardening practices in hawaii and how they differ from gardens here. What are the restrictions and advantages? Are there limits to what you can grow?

[rainbowgardener]

That would make a nice separate thread, if you feel like doing it, imafan.

[Lucius_Junius]

When I worked in aquaculture, we would bring in nets that had been in the sea for nearly a year, fold them up, and store them in the parking lot until they were ready to be sent away and cleaned. These nets were literally so encrusted with marine life - mostly seaweed, barnacles, and shell fish - that they would begin smoking in a couple weeks. By the time the cranes unfolded them to put them on the truck, they were literally billowing smoke. That said, I never saw, nor ever heard tell of, any of them actually catching on fire. These nets were gigantic and held an enormous amount of decaying organic matter. Now I wish I'd taken some home with me.

[mtgarden gal]

Good story! I bet your garden would have loved those net scrapings!

[ElizabethB]

My 2 cents - I NEVER put soil, compost, anything like that next to my house or other structures. Bad news. Ring the dinner bell for termites. Soil erosion from the dripline. Soil back splash on the wall. Create a gravel barrier between your structure to 6" outside of your drip line. As for compost - my bins are are at the back of my yard. I have 2 4'x4'x4' bins. It makes it easier for me to toss and turn. My bins steam in the spring and fall. Never have a problem with fire threat. It rains too much for that to be an issue. If we do fall into a drought - which happens - a hose stuck in the bin usually takes care of any drought conditions and keeps my bin cooking..

Good Luck

[mtgarden gal]

Thanks ElizabethB! You make some good points

[toxcrusadr]

While it's fairly easy to find cases of compost fire, there's no way to count the millions of compost piles and bins that cook merrily along without any problems. It's about as likely for yours to catch fire as it is for you to be struck by lightning.

[imafan26]

Some backyard compost piles have the opposite problem. They don't get hot enough from either not enough balance between green and browns, moisture and mass (height) to heat the center.

Fires or smouldering usually is a problem with large piles of decaying matter that have a lot of wet greens in them.

The other reason not to put the compost too near the house, it attracts all kinds of critters, centipedes, roaches, sow bugs, ants,mice. You really don't want them getting into the house.