Has anyone experimented with adding heavy insulation around their composting bins?
I have access to a large amount of 1" and 2" insultation. I have been trying to work out whether I will get much benefit from insulating my bins, or whether the reduction in airflow around the heap would offset any benefits from keeping heat around the stack.
I am thinking about making a series of 1 meter cubed bins and then insultating them at the sides and top with 4 inches of packing to keep the heat in. Turning would be done as usual with a fork every couple of days.
I attempted to make my own version of a 'hotbin' (the commercial name)- ie a wheelie bin with expanded polystyrene insulation on the sides- holes drilled near the bottom and in the top for airflow. It was a 240L wheelie bin- so not as big as you're planning.
It did work- as in the compost got very hot and the volume cooked down pretty fast, but it was a lot of work to stop it going too wet and anaerobic (as is the commercial version, you end up having to add things like woodchip to keep the structure open and then sift it out later for reuse)- I prefer very much to plonk all my stuff in a heap and leave it for a few years, let the critters do the mixing. Perhaps if I really wanted weed-seed free compost and things.. but I just don't care that much, for my garden really rough compost full of bits of twig is fine!
I have considered using converted freezer or fridge shells for hot composting or a year round outdoor worm bin.
There are lots of compost augers out there, if they work they could be a compromise between fiddling with it all the time and doing nothing at all.
In "Worms Eat My Garbage", Mary Appelhof details how a Canadian set up a roughly 1 cubic metre outdoor worm bin for year round composting. It was a simple design, Styrofoam insulation board lining four plywood walls fastened by a couple bent eye-hooks on each edge. The cover was a sheet of 6 mil plastic vapour barrier with a four inch thick Styrofoam lid, slightly smaller than the bins width to float on top and allow sufficient air for worms and other composting lifeforms.
Sounded excellently simple, I'm going to try it this fall, as my worm population has outgrown my kitchen bin and I want more castings with as little maintenance/work as possible. I'll just build it on one of my existing raised vegetable beds, and move it around every time I need to empty it to benefit the soil.
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