Discarded wood shipping pallets are an inexpensive material from which to make compost bins. Many are constructed from sturdy hardwoods and they are fastened together with special nails to resist rough handling. Garden centers, hardware stores and building supply companies will often let you take a truckload of pallets for nothing.
The most common sizes for wood pallets in the United States are 48 x 40 inches, 42 x 42 inches and 48 x 48 inches. To make one compost bin, select four pallets of the same size. If this is not possible, select two pairs of same-sized pallets. One matching pair can form the front and back, while the other pair can be used for the sides. Choose pallets in good condition, without rot or broken boards.
Choose an appropriate site for the compost bin. It should be on fairly level ground and as close as possible to your kitchen door. Trudging through snow or rain to get to a compost bin at the far end of the yard will discourage you from composting everything you can.
Pallets have two different surfaces. The top side has boards set close together. The underside has fewer boards spaced farther apart.
Both you and your helper should wear gloves. Pallets are heavy, made from rough wood, and often have steel staples and protruding nails that can cause nasty injuries. Remove as many of these hazards as possible before you begin construction.
Set two pallets on their edges, at right angles to each other, with the top sides facing outwards and the boards running left to right, parallel to the ground.
Place two brackets on the outside of the corner formed by the pallets. Arrange the brackets at points roughly equidistant from top and bottom, and where the screws you will use to secure them will get the most places to grip. Every pre-drilled hole in the brackets should be over a firm piece of wood. Drive the screws home through the brackets and into the wood, just until they are snug. Do not over-tighten.
With the two pallets now forming two sides of your compost bin, arrange the remaining pair of pallets to form a square. Secure the corners with brackets and screws, following the same method described above. Your compost bin is ready for use!