Building an outdoor compost bin is a great way to set your yard up for this spring and all the seasons to come. Building an outdoor compost bin is a do-it-yourself project that can be made with readily available materials, including recycled or salvaged material.
Before you start building your compost bin, pay special attention to location. Although you want your compost pile to have sunlight exposure to help raise the pile temperatures, too much sun in summer can actually help raise temperatures too high. Rainfall will help keep your pile moist; locate the pile away from building eaves and other barriers to rainfall. Be sure to think about how the composter will fit in with your existing landscaping, and consider applicable local guidelines or building codes. Keep the composter in a well-drained site, away from direct contact with buildings and trees or shrubs, to reduce possibility of moisture damage to plants or buildings.
There are several design options for your outdoor composting bin. The two most common designs involve either a single bin or a multi-bin unit. A single bin is really just an adaptation of the classic compost pile, using wire, wood, or other materials to confine the compost. Be sure the bin construction allows for plenty of air circulation and that the bin is also big enough for the compost to heat up. Most guidelines call for a bin at least three feet wide by three feet long and three feet tall. Single bins can also be made by upcycling used snow fence, held by posts in a circle with a 3- to 4-foot diameter.
Compost made in a single bin will not be ready to use for many months or even a year or more. That makes a multi-bin outdoor composter an alternative suited for many yards. A multi-bin unit allows you to keep compost in several piles in similar stages of decomposition, helping create finished compost fasters.
A three-bin unit is the most common multi-bin design. Three-bin composters can be constructed as a weekend project using basic tools. They are most commonly made from rot-resistant wood like cedar or wood that is pressure treated with non-toxic materials. Hardware cloth (poultry wire) that is galvanized or coated is used for the walls of the three bin unit. A free design plan for a basic three-bin unit is available from the University of Arkansas at https://www.uaex.edu/publications/pdf/FSA-6033.pdf
Recycling used wooden shipping pallets is another way to upcycle materials into a functional compost bin. Shipping pallets can be obtained for free or very inexpensively from many businesses. Preparing a level site and adding some brackets and hinges, and perhaps re-nailing or reinforcing older pallets, are the main things needed in addition to the pallets themselves. A free plan for a single bin unit made from shipping pallets, which can be duplicated to create a multi-bin unit, is available from the University of Florida: http://baker.ifas.ufl.edu/Horticulture/documents/ShippingPalletComposter.pdf