Compost improves soil structure and adds vital nutrients to shrubs, perennials, and annual flowers and vegetables. Making your own compost turns lawn waste and kitchen scraps into a valuable garden addition, and using a compost bin helps speed that process. While expensive composting units are available from garden supply stores, there are several ways to easily construct your own compost bin using inexpensive, or free, materials.
Wooden pallets are often available free from large stores, warehouses or municipal recycling centers. Find three pallets of similar size and stand them on end in a "U" shape to create a single-bay compost bin. Add two additional pallets in an "L" shape to create each desired additional bay. Secure the pallets together permanently with long wood screws--but for an even cheaper, more flexible configuration, simply tie the pallets together in position with several lengths of baling twine or recycled bakery-box string. With a multi-bay compost bin, cut the twine and remove the intervening pallet to more easily turn the pile into the next bay, then replace the pallet and tie it with new lengths of string.
Galvanized wire mesh can either be arrayed in an upright tube, held to the ground at the base with tent stakes, or wrapped around metal fence posts. Light chicken wire is the least expensive, but hardware cloth or turkey wire will last considerably longer for a minimal additional investment. Wire mesh compost bins are also easy to wrap in black plastic to help heat the pile up in cooler weather.
Straw bales can be used as "building blocks" to construct a one-bay or multiple-bay compost pile. Straw bales are inexpensive and provide superb insulation, but they do have the disadvantage of being bulky. You must have at least six rectangular bales to create a single-bay compost bin. Use straw rather than hay, to avoid weed seeds infesting your compost.
Plastic Barrels and Garbage Cans
With proper drainage and an opening to remove compost, a plastic rain barrel with its top cut off, or a large plastic garbage can, may serve as a small, contained compost bin, which is also reasonably secure against vermin--an important consideration in more urban locations where an open compost bin might be unwelcome.
Drill numerous 1/4-inch holes in the bottom half of the barrel or garbage can. Then, cut a circle out of the bottom, leaving at least 2 inches of material around the outside of the circle. Place two sticks parallel inside the container across the hole in the bottom, and put the cut-out bottom on top of these sticks, forming an elevated bottom that allows drainage and is also removable (to access the compost).
Alternatively, drill holes in the bottom as well, then cut a flap out of the side of the barrel or garbage can near its bottom (large enough to get a shovel into) for compost removal. Use duct tape or a bungee cord to secure the flap shut.