Insulated wooden compost bin

I'd like to make a large (1.5m3) wooden compost bin that's insulated to try to run the compost hot. My existing bins are crap and it just sits there slowly turning into mush despite turning and the bottom being open to drain.

I propose to use 2 layers with foam board in between (I have celotex offcuts/damaged pieces which would be ideal).

The base will be insulated too and I'll probably run a couple of perforated pipes through to allow some air to the middle.

The outer layer I think will be decking type wood - it looks nice enough, it's tough and simple to screw into a box shape with some batten at the corners.

Question is what to make the inside surface of? Same? WBP ply? Something else?

There'll be drain holes in the base to allow leachate to run off (doubt there'll be enough to bother collecting). It's going to (hopefully) get hot and steamy inside to the inner layer will be in a much harsher environment than the outside.

Obviously the concept of toxic preservative on the inner layer is a no-no.

Cheers

Tim

Reply to
Tim Watts
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Do bear fire in mind. I had a small pile of hay raked up into a mound, that had been used when we were lambing, so it had just a bit of sheep urine and poo but was pretty clean. Left it sitting in an open barn intending to re-use it. Wife pointed out one day it was smoking. Been there perhaps two weeks. Opening up the pile showed it was very close to spontaneous combustion.

So locate away from buildings, and turn very often.

AWEM

Reply to
Andrew Mawson

I once used corrugated iron sheets for the sides and roof of a compost bin. At one stage it got so hot in the sun that the grass clippings burnt.

Reply to
fred

Mine is made of old palettes with shed doors as separators. I have three used in rotation and turn them as little as I can get away with. The rough bits from the being emptied one end up on the being loaded one and so transfer the culture from one heap to the next.

To bootstrap a hot heap it helps to add some proprietory accelerator like Garrotta the first time (and just the right amount of water). This is more important for small domestic garden heaps.

I find that despite what is generally believed it doesn't much matter what you do provided you add about 2m^3 of stuff at a time it gets hot. I have seen big piles of conifer branch offcuts steaming like crazy in mid winter and fumes of oil of wintergreen on the air.

My scrap palletes disintegrate every couple of years. If you wanted to line it with something to stop the rot then thick polythene maybe? (my instinct is this is a waste of time)

It will get hot enough to catch fire if you do it right/wrong and insulate too well depending on your point of view. I would be tempted to try wooden sides and Celotex offcuts wrapped in roofing felt or pond liner from the front and sides and just ignore the bottom - a palette or even nothing at all is good enough down there...

It will rot away no matter what you treat it with. A hot compost heap is an aggressive environment and astonishingly hot sometimes. It smells funny too when hottest - not entirely unpleasant but a bit odd. The smell is apparently short chain fatty acids and similar to BO.

Site it well away from the house or you will not be popular. (and also well away from anything that will burn!)

I have had mine up to smouldering a couple of times!

Reply to
Martin Brown

On Thursday 20 June 2013 12:48 Andrew Mawson wrote in uk.d-i-y:

Ooh.. This will be down well away from the house down by a fence. OK the fence would get it but that would not be a disaster.

I've seen stuff steam but not get *that* hot. I assumed the extra heat would slow the bugs down - or was another exothermix process taking over I wonder?

Reply to
Tim Watts

On Thursday 20 June 2013 14:01 Martin Brown wrote in uk.d-i-y:

Thank you - that was food for thought...

Reply to
Tim Watts

On Thursday 20 June 2013 18:00 Mark wrote in uk.d-i-y:

I've had those too (Slow Worms).

Reply to
Tim Watts

I just use pallets with a DPM around the inside and a bit of old carpet on top it doesn't get steaming hot but everything rots down eventually and you get interesting wild life making a home in it.

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Reply to
Mark

How can you tell without a video? ;-)

Tim

Reply to
Tim+

I think your concept is wrong and possibly dangerous. If the contents are turning to mush, something is wrong. Probably the contents and possibly the construction of your compost bin. As stuff decomposes it will generate heat. Slowly, steadily and surely. I've had some real steamers. Like many I use a series of wooden pallets. Open to the ground and covered with a bit of old carpet. No insulation. Turned (very infrequently) when I'm not up to other more pressing stuff. Open to the ground is fairly portant, to me anyway. The good folk at uk.rec.gardening would be able to give better advice. Nick.

Reply to
Nick

If you want a cheap solution, a few pallets nailed/tied together plus a few stakes. Lasts three or four years. You can undo the string to get the stuff out. The important thing is to have a rainproof lid. Say a bit of old roofing. Insulation is unnecessary. You might need to water it occasionally but lots of cold rain is bad. It should rot down in three or four months in Summer, six months in Winter. There will always be some that doesn't rot in a small heap. Doesn't seem to matter, dig it in anyway.

Reply to
harryagain

"In recent years slow-worm numbers have declined dramatically, mainly as a result of habitat loss and intensive land-use. The remaining populations in allotments and gardens are now especially important to the survival of this species. They are really beneficial to gardens as they eat a variety of pests, so if you have any, please look after them. Have a compost heap which allows slow-worms to crawl through it and feed inside."

all the more reason not to build a Hot Fusion compost heap ;)

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Reply to
Mark

On Thursday 20 June 2013 21:32 Nick wrote in uk.d-i-y:

Undoubtedly - the garden "came" with a couple of those crappy "free council hand out" jobbies - completely useless. Does not retain heat and no air holes. I carefully placed in paving slabs spaced apart to allow excess liquid to drain and worms to get in. Still tends to not work at all well.

I have never had that. It gets warm once in a while when I dump a load of grass in. That was my reasoning for insulating it. The worms like the kitchen waste - but its that part that turns mushy. I do not have much dry material like leaves or paper.

Perhaps that might help?

I was taking design hints from this:

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which is insulated, central air pipe and a rediculous price!

Reply to
Tim Watts

On Thursday 20 June 2013 22:40 Mark wrote in uk.d-i-y:

Valid point. Although the slow worms are sharing my bin of crap with a rat or two - caught the bugger legging it in the other day...

Reply to
Tim Watts

The free council handout ones are OK for making leaf mould which is a slow cold process and takes a couple of years at optimum conditions. I turn mine once a year (I compost more than is permitted in the green bin and use that for leaf mould production as well).

The usual reason for not getting a compost heap to behave is never putting enough material on it at a time for it to get properly hot.

You shouldn't really put deciduous tree leaves in as they contain antifungal components that can stall a compost heap. Better used to make leaf mould elsewhere.

You are over engineering it. Sides and a simple cover to keep a bit more heat in might help but the heap also needs air so palettes are ideal. The trick is in keeping the heap properly aerated since if it goes anaerobic then you get slimy mush and unwelcome smells.

Reply to
Martin Brown

Urine works just as well and is cheaper Just piss in a bucket for a day and add that to the heap.

To get a heap hot you just need enough material - a hand full of kitchen waste or one grass box of cuttings at a time is unlikely to get the temperature up.

This time of year I can fill a large compost bin with my grass cuttings. I mix this with other household waste, cardboard, shredded paper etc. and the thin walled plastic bin will run hot for week.

I have another couple of bins that run cold but have many hundreds/thousands of worms doing the work. They live in the top few inches so the bin is ideal for adding small amounts of waste at a time. These are not the expensive worm refuges advertised as a solution for small household. They are ordinary "darlek" bins with an open base, placed on soil and populated by the worms that have found the bin themselves. It takes perhaps 12/18months to get a bin full of usable compost.

As someone else has written, my larger bin is situated on earth and has holes at the base and attracts many slow worms. When I last emptied it I found 8 slow worms, next time I will check more carefully when they breed to ensure that I don't disturb them during this period.

Reply to
alan

That just supplies extra nitrogen which in a heap with too many grass cuttings already will only make matters worse and more ammonical. The advantage of Garrotta is that it is free dried fungal mix and some ammonium salts (you can cut it with much cheaper ammonium sulphate). It is in effect compost starter culture with the right mix of fungi and bacteria to get things going the right way. It is ideal for making a small domestic heap go hot reliably. I don't often recommend proprietory products but this one really does do what it says on the tin (unlike a certain paint product I could mention).

Most problems are down to squishing the stuff down too hard and making an anaerobic heap of slime. Adding shredded brown cardboard to bulk it up and provide some transient insulation should help. I don't bother. A lot of what is written on the net about compost heaps is really rather odd American gardeners obsessing about C to N ratios.

And that I suspect is the OPs primary problem. A 1.5m^3 heap isn't big - my heaps are about 6m^3 each and rot down to about 2m^3 of compost.

My heap has variously had grass snakes, frogs, toads in it (and the odd rat which I do see off). Never had slow worms that I have seen. It is a surprising to get so many amphibians lurking as the nearest permanent water is at least half a mile away and across a road!

They also hide under my lowest hedge where there is a borderline spring during wet winters but just slightly damper dark cool ground in summer.

Reply to
Martin Brown

Why does composting always bring out the Russ Andrews in people?

Just collect it all, pile it in a heap and leave it for 3 years.

If you want it composted quicker than that feed it to a rabbit or a horse or a goat. Hint: you get to eat the horse/rabbit/goat afterwards as well.

Reply to
The Natural Philosopher

The advice I saw in uk.rec.gardening was: Compost needs three things to rot well:

- air

- water

- time

If you have some old compost that hasn't rotted properly, add whichever of the first two is missing (via turning+shredded cardboard or a watering can), and wait a bit more.

Reply to
Martin Bonner

+1 thats the biggest problem with grass cuttings. They tend to go all syrupy and end up anaerobic. And then a different sort of bacteria get involved and they smell like bad teeth. Really vile. we tend to mix em with leaves and tiggy stuff.

yep.

Reply to
The Natural Philosopher

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