To save space, hasten decomposition, and keep the yard looking neat, it is recommended that the compost pile be contained in a structure. Composting structures can be made of a variety of materials and made as simple or complex as desired. There are many options available that can be tailored to individual needs. Listed below are a few suggestions for containing the compost.
A barrel or drum composter generates compost in a relatively short period of time and provides an easy mechanism for turning (Figure 1). This method requires a barrel of at least 55 gallons with a secure lid. Be sure that the barrel was not used to store toxic chemicals. Drill six to nine rows of 1/2-inch holes over the length of the barrel to allow for air circulation and drainage of excess moisture. Place the barrel upright on blocks to allow bottom air circulation, fill it three quarters full with organic waste material, and add about 1/4-cup of a high nitrogen containing fertilizer. If needed, apply water until moist. Every few days, turn the drum on its side and roll it around the yard to mix and aerate the compost. The lid can be removed after turning to allow for air penetration. Ideally, the compost should be ready in two to four months. The barrel composter is an excellent choice for the city dweller with a relatively small yard.
Bin-type structures are the most practical for larger quantities of organic waste. For example, a circular bin can be made by using a length of small spaced woven wire fencing and holding it together with chain snaps (Figure 2). The bin should be about four to five feet in diameter and at least four feet high. A stake may be driven in the middle of the bin before adding material to help maintain the shape of the pile and to facilitate adding water. With this design, it is easiest to turn the composting material by simply unsnapping the wire, moving the wire cylinder a few feet, and turning the compost back into it.
A three-chambered bin is a very efficient and durable structure for fast composting (Figure 3). It holds a considerable amount of compost and allows good air circulation. The three-chambered bin works on an assembly line idea, having three batches of compost in varying stages of decomposition. The compost material is started in the first bin and allowed to heat up for 3 to 6 weeks. Next, it is turned into the middle bin for another 4 to 8 weeks, while a new batch of material is started in the first bin. Finally, the material in the middle bin is turned into the last bin as nearly finished compost and left to cure until finished composting, usually an additional 5 to 16 weeks.
To make this structure, it is best to use rot-resistant wood, such as redwood or cedar, or a combination of wood and metal posts. Unless the wood is rot resistant, it will decompose within a few years. Each bin should be about five feet by three feet and about four to five feet high. This volume is ideal for maintaining heat and at the same time is manageable for turning. Using removable slats in the front offers complete access to the contents for turning.
There are many other structures for composting, and no one structure is best. Invent your own, or for a more thorough description of different structures, refer to Rodale's Complete Guide to Composting4. If you don't want to build a structure, there are several commercial composting units available through local garden stores or mail-order catalogues. Make sure that these units meet the minimum size requirement of one cubic yard or larger in size so that you have a large enough mass to self-heat to 130 degrees F-150 degrees F.