Simple Stackable Compost Bin from Pallets Collars
Build Instructions:
http://www.instructables.com/id/Simple-Stackable-Compost-Bin-from-Palle…
How it works:
https://www.youtube.com/watch?v=Tgtd88kKIn0
With one single unit as opposed to two or three bins, the space needed for composting is minimized. Each tier stacks on top of the other, latching together to make the bin. This setup makes it easy to turn and rotate the compost, since moving the collars is simple. Just remove the top collar and place in a new location adjacent to the original bin location. Turn the compost into the new location and stack the collars until finished. This is a great alternative to having multiple compost bins next to each other.