Compost heap safety

[Frnc]

Ok, decision. Just moved mine a few feet further away from the house (about 20 feet away now). The plastic gate was facing away from direction of travel so it slid up under the pressure and everything piled out! At least it got stirred properly. Had to use a shovel and a rake to gather it up and carry it to the new site. Turned it 90° so the gate is to the side, bit late now.

[British Red]

It's perfectly possible for damp vegetation to catch fire. Damp hay does it in haystacks (so called rick fires). I'm sure we've all seen steam rising from a midden on a Winter's morning. I've got video of fresh woodchip (containing leaves) with steam pouring off it.

Ultimately the process of decay gives off heat, but decay also needs water, so damp stuff catching fire is unlikely. What can happen though is that the moisture sinks to the bottom creating rot & a hot spot while the top stuff dries in the breeze. If the top stuff is fine ..like hay...and well mixed with air rather than compressed (like the top of a hay rick) you get a good mix of fuel, heat and air and up it goes.

I doubt that most domestic compost heaps get big enough or the right conditions for this to happen often, but on a farm, its a risk. It happens less now that the switch has happened to silage from hay, but it still does occasionally

[grenfell]

Interesting reading the links and comments on a subject I'll admit to previously knowing next to nothing about. I suppose ignorance is bliss as the saying goes but even though I now know about the phenomenon I'm a bit more satisfied I'm not going to walk outside to a bonfire. It does seem to require a pretty specific set of circumstances . My main heap is around a cubic metre and a half and is built of brick with only the front having timber boards. It's open at the top so gets rained upon. I have a smaller plastic one that's also open at the top and a couple of builders sacks of leaf mould. I don't think I'll be losing sleep over this...

[jansman]

Interesting reading the links and comments on a subject I'll admit to previously knowing next to nothing about. I suppose ignorance is bliss as the saying goes but even though I now know about the phenomenon I'm a bit more satisfied I'm not going to walk outside to a bonfire. It does seem to require a pretty specific set of circumstances . My main heap is around a cubic metre and a half and is built of brick with only the front having timber boards. It's open at the top so gets rained upon. I have a smaller plastic one that's also open at the top and a couple of builders sacks of leaf mould. I don't think I'll be losing sleep over this...

I have 6 plastic jobs,open topped. They get warm,as heaps do,but like yourself,I am not concerned. In fact ,I shall turn a couple over later to get some worms for fishing in the week.

[grenfell]

Almost forgot the two on the front garden . They're the plastic dalek type with lids but are shaded from bright sun so not raising the anxiety stakes either.

[korolev]

Mine doesn't get above 20c

[jansman]

Mine doesn't get above 20c

P#ss on it! The nitrogen it adds helps the process enough to raise the heat.

[jennyjj01]

Mine doesn't get above 20c

Don't be jealous.
Mostly mine don't either . 2 x Plastic 300l ones.
But for a few days after loading them up with some leaf mould and grass clippings, they just sprung into life. Must have just hit the sweet spot with ingredients. Only achieved that for a few days. A bit of 'additive No#1' seems to help, especially on the corrugated cardboard in there..

They still seem to rot OK when the mix is wrong and the temperature is low. Just slower.. Can't fill the beggars, because every time I look, they've slunked down.

Back to the topic, I think it's huge overkill to fear a domestic compost heap spontaneously combusting.

[jennyjj01]

Duplicate. Please delete

[jennyjj01]

P#ss on it! The nitrogen it adds helps the process enough to raise the heat.

You told me off for getting MrJJ to do that that Something to do with discretion and using buckets.

A portion of pee per day certainly keeps the moisture content right.