fires in potting soil

I have investigated several fires that seem to start in potting soil in plastic or wooden boxes, that have dead plant materals and commercial fertilizers. All have occured on or after a sunny day. These fires seem to have no other heat source. Is any one else experincing this? Has there been any scientific reseach on this topic?

Are you able to rule out disposal of smoking material in the potting soil? What I do know is that Potting Soil is different than Dirt.

Potting soil is full of organic material that will support smoldering combustion.

Brian

potting soil gets damp, heat of day causes stuff to warm up, and sometimes visible fire.

http://www.ctv.ca/servlet/ArticleNew...Canada&s_name=

Peat moss and stuff like that will actually burn..even underground for some time. Some potting soils contain peat. Further, (If I'm not mistaken) wet damp stuff will break down via bacteria and THAT creates heat.

I never say never. but all of the owners of the flower potts have denied thowing smoking matereals in them. On the last one, some one would have really have had to go out of their way to do so.

You really shouldn't be having "a lot" of these.

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Originally Posted by Donny Snider WWFD

I never say never. but all of the owners of the flower potts have denied thowing smoking matereals in them. On the last one, some one would have really have had to go out of their way to do so.

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Yes, nobody EVER smokes over where the origin is :)
(corrollary, nobody was smoking the day of the fire)

Self heating of organics is a known phenomenon, but on a standard planter where you may have one bag of the "organic" soil, there is not enough mass to get the process started. If there were, then you would have the garden centers where the bags are stacked on pallets going up like crazy.

There is some news out there about fire department investigators determining the origin as the planter, and the cause as spontaneous combustion. Unfortunately, this generates statistics which then feed upon themselves and are used to justify attributing more fires to this cause.

I have not found any reputable study that shows someone was able to recreate a spontaneous heating event in a pot or planter. Also, by the way, I did not find any non-reputable study.

Brian

Thanks Brian, it looks like I will have to do some experimenting on my own.

http://www.firefindings.com/tools/index.html


put in potting soil in the search box

Here is a fire that started in soil on a porch: http://www.firehouse.com/showcase/ph...ota-house-fire

this doesn't surprise me. compost piles often catch on fire due to heat from anaerobic decomposition. this could be the same, but on a smaller scale.

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Originally Posted by 19fire90

this doesn't surprise me. compost piles often catch on fire due to heat from anaerobic decomposition. this could be the same, but on a smaller scale.

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The problem is that self heating does not scale down. Part of the process is that the self heating takes place in the middle of the pile and the other stuff insulates that so the heat builds up. With a small pile such as is in a planter or pot, there is not enough insulation.

One wet bale of hay will not self heat, but fill a barn and you might get something going.

Brian

We recently had a fire in a planter that was the result of an insents stick. They typicly burn away to nothing and would appear as if it was spontainous combustion in the soil itself, or materials in the soil.

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Originally Posted by Breech31

Peat moss and stuff like that will actually burn..even underground for some time. Some potting soils contain peat. Further, (If I'm not mistaken) wet damp stuff will break down via bacteria and THAT creates heat.

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Many brands of potting soil contain peat; peat is used as fuel in some parts of the world. It's not very good, but it works well enough.

Potting soil frequently contains matter like manure, and slash (what's left over from harvesting trees- mainly bark). Slash fires that autoignite aren't uncommon. If not composted well enough, these would provide excellent energy sources for microbial action.

I can't seem to find reference to potting soils, manure, or slash in Bowes' text on self-heating, but I remember very distinctly a reference on some bagged product (bark?) as I consulted on the subject some years ago.

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Originally Posted by truckie101

I can't seem to find reference to potting soils, manure, or slash in Bowes' text on self-heating, but I remember very distinctly a reference on some bagged product (bark?) as I consulted on the subject some years ago.

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You did not mention what the size of the pile was that autoignited, and that is an important peice of information.

There is no debate as to whether potting soil will burn; the question is will it burn in the bag or in the planter. I say the pile is too small to heat so there is some other explanation.

Brian