Building a compost bin is an easy chore for an hour in the garden and you’re smart to be thinking of building it yourself. Most of the commercially made bins are too small to support an active compost system that heats up. They simply don’t have the necessary volume to do the job.
Minimum Size for Hot Compost
When building a compost bin yourself, you can easily achieve the minimum size of a 4×4 foot space (or close anyway) that will support enough organic material for a compost pile to heat up to the correct temperature.
Easiest Compost System I Ever Used
The easiest way is to obtain four used skids (or 7 as you’ll find it easier to make 2 units) I recommend you find some wire that will be used to hold the skids upright and together and, turning the skids so they are vertical, that you simply make a square out of them by wiring the sides together. This will give you a cube approximately 4x4x4.
This first square/cube also allows you to make a second square by using one of the skids as a common wall. The other three unused skids form a second cube and now you have two active bins only occupying a space measuring 4×8 feet.
Pick one side to be the door side where you’ll open the compost bin from (leaving the other three sides alone) to dig or remove finished compost. This “door” side is usually wired heavier on one side than the other to act as a hinge. The other non-door sides should be securely wired as there could be significant pressure from the weight of yard wastes. Securely wiring it also stops dogs from digging around in it (something my old lab found irresistible.)
Here’s what great compost looks like – brown and crumbly
Another Easy Compost Bin
A second system for building a compost bin involves making a circle out of snow fencing. You can pick up a short role quite inexpensively at most building supply stores
Simply take a length of fencing approximately 12 feet long and make a circle out of it. Wire the ends together, place it where you want it to sit and start filling. This makes an excellent in-vegetable garden composter where you can dump all the trimmings and thinnings.
Do plan on using the wooden slats and be careful or you’ll break those slats. A few broken ones doesn’t hurt anything (they can be taped or lashed together) but again, larger holes allow dogs to enter.
This is a very light system that can be easily taken apart and moved around in the garden at a moment’s notice. It is not as long term or durable as the skid system.
Some writers suggest driving stakes into the ground as supporting uprights and then wiring plastic snowfencing or some other enclosing material to those stakes. This works well even if it is a little more work to construct.
Doug’s Summary Notes
The point really is to get an area that is at least 4’x4′ and build sidewalls at least 4′ tall to create enough thermal mass to really allow the pile to heat up.
Anything you can use to meet this size requirement – from snow fencing to cement blocks to railroad ties will do the job.
Or, you have to get your nitrogen to carbon ratio dead on.