Composting Yard Waste: Location and Structures

Choose a composting site carefully. Partial shade avoids baking and drying in summer but provides some solar heat to start the composting action. A site protected from drying winds prevents too much moisture loss. Another consideration is convenience for moving volumes of plant materials in and out of the area. Choose a site close to where material will be used, but not highly visible or that interferes with yard activities.

Structures aren’t necessary for composting but do prevent wind and marauding animals from carrying away plant wastes. Open compost piles can be used in less-populated rural locales, but structures are a near-must in urban areas. Many composting structures can be purchased or built (Figure 2). They vary in how well they can be managed to meet the requirements for effective decomposition under Colorado environmental conditions. Many people cover their compost with plastic to prevent the outer layers from drying too much. Remove the covers periodically to add more water and plant material and to aerate the mass.

In-ground pit composting presents problems with turning or aerating the plant material and also can pool water, which leads to undesirable low oxygen conditions.

A minimum volume of material is necessary to build up the heat necessary for efficient composting. This volume is generally around 36 inches by 36 inches by 36 inches. Well-insulated wood or plastic structures can be smaller and still hold enough heat to compost well. Wastes should heat up within two days if the compost is put together correctly.

Structures built of wire also may have drying problems. This depends on how many sides are exposed and whether exposure is on the windward side. Plastic covers or tarps often must be used with wire bins. Wood structures do not dry as much but are generally more expensive to purchase or build. An efficient wood structure is the three-chambered bin system that allows plant material to be aerated by turning it from one bin to the next as it decomposes (Figure 3).

Compact plastic composters are available through Garden centers and catalogs (Figure 3). They work well for small yards that produce few plant wastes. Some of these use a vertical composting system where fresh materials are added to the top and finished compost is removed from a drawer in the bottom. This system requires an aeration tool to reach in and stir plant materials on a regular basis. If you use metal barrels for composting, drill holes to allow air to enter. Turn the barrel on its side and roll it to mix and aerate the compost.