[edstrong]

I'm about to redo our composting system and plan to create some new bins out of corrugated metal sheets and wooden posts. I have (within reason) as much space as needed in the veg garden: I may build a line of them, perhaps 3-4 so I can rotate the contents.

How big is the optimal size for a compost bin? I want each of mine to be big enough to generate enough heat to compost well but small enough to be manageable. I was thinking of perhaps 4 foot square. I'll be putting in a mixture of kitchen waste, garden waste, chicken coop mess, some grass clippings (no weeds though, I just don't trust the composting to be good enough to kill all traces). Thoughts please!

[macgro7]

As big as the amount you want to produce 

I chuck most waste inside the chicken run. They do all the work scratching and turning.

[doganjo]

Yup, then you rake the chicken run, put it in the compost bin with some greenery and get good compost a couple of months later

[Fleecewife]

The ideal size is usually suggested as a metre square, but if you can manage a bit bigger and you have enough stuff to fill it, then go for it, remembering that the heaps go down quickly, and your volume includes depth, when you are considering heat retention. Also, what you can manage might depend on your height for reaching to the back.
If you have a row of bins, then they each keep eachother warm in the row (but you might find that metal gets quite cold at the ends - maybe insulate it with wood).  Be sure to design them to make it easy to turn one into the next from time to time.  It's hefty work, which you should really do a couple of times a year.  I couldn't manage that, but my grandson loves turning the heaps and makes a point of doing all three in little more than an hour.  He's young, strong and fit, so be realistic about what you can manage. I had originally planned a pair of compost heaps in such a way they could be turned with a tractor front fork loader.  It didn't work though as at the time of year it needed to be done, the backwards and forwards repeat motion just chewed up the ground horribly.  So we scrapped those and build a row of three.  I have heard of people turning their heaps using a rotavator, but that hasn't worked well for us.


I actually don't mix my animal cleanings with the vegetable waste, but compost the two separately.  This is so I have rich FYM and milder compost for different purposes.  We also collect the used straw from the sheep field shelters every couple of years, mince it with a rotavator and use that on the outside beds - grows wonderful spuds!

[Anke]

Ours are just 4 pallets in a square. But if you want more info, Charles Dowding is taking compost making to a higher level than most of us. Good youtube videos.

[edstrong]

Thanks for the feedback everyone.

As I'm going to make the bins out of sheets of corrugated steel the sizes of these will likely define the size of each bin - 6 foot long and 3 foot high. The width is up to me as the end panels can overlap: perhaps 5 foot wide for these. And a total of three bins, to start with. Should be easy to transfer contents from one to the other as they will be separated by a single sheet (just need the strength to lift everything over the 3 foot).