A bin helps contain your compost pile and makes it more attractive. While you can buy a commercial plastic container from a garden center, it's easy to build your own. A simple round or square structure can be made from fencing wire. The bin should be at least 3 feet wide and 3 feet deep to provide enough space for materials to heat up. Use untreated wood or metal fence posts for the corners, and wrap wire fencing around them. The fence mesh should be small enough that materials won't fall out. When the compost is ready, unwind the wire and scoop the compost from the bottom of the pile. Then re-pile the not-yet-decomposed materials and wrap the wire back around the heap.
More permanent bins can be constructed of wood or masonry blocks. Here, boards are added to the bin's front as the pile grows taller.
While one compost pile is good, many hard-core gardeners feel three is better. By building a trio of bins, you can compost in stages: one bin will be ready, one will be brewing, and one will just be starting. A triple bin is best for a more active composting system. Turn the pile into the next bin when it reaches peak internal heat.
Tumbler-style composters come in several configurations. The most common is the horizontal drum mounted on wheels or axles to allow mixing of materials.