Composting provides organic material to improve soil and reduce wastes that reach landfills by 20 to 30% or more. (Photo courtesy: CSU Extension Boulder County).

Trees are beginning to lose their leaves, your garden plants are done and if you don’t have access to commercial composting pickup, you may want to try composting in your yard. Composting is not as difficult or as time consuming as you think. Composting provides organic material to improve soil and reduce wastes that reach landfills by 20 to
30 percent or more.

You do not need a fancy compost bin unless your homeowner’s association has a covenant requiring one. A simple pile with some space to be able to turn it is all you need. Materials that you can put into a pile include leaves, garden waste, spent blossoms and vegetable scraps. Materials that you do not want to put in the pile are milk products (cheese and yogurt), meat scraps, eggs and pet wastes. These materials can make the pile smell, attract animals and spread disease. If you live in an area where bears visit, you should put only yard wastes (minus any fruit such as apples) in the pile so that you don’t attract them to your yard. Locate the pile so that it is convenient to add to, turn and where water is easily accessible.

Compostable materials are divided into brown (carbon source) and green (nitrogen source) materials. Brown materials include straw, dry vegetation and leaves. Green materials include kitchen scraps, grass clippings, cuttings from perennials and garden wastes. When building the pile, you need a 30 to 1 ratio of brown material to green. This works out to approximately an equal volume amount of each. Shred or cut up the materials to expose more surface area and accelerate the process. Place about four inches of brown material to start the pile and then place about four inches of green material on top and mix the two layers together thoroughly while watering the materials. Compost should be like a wet sponge that when squeezed gives just a few drops of liquid. Continue adding layers, mixing and watering until all the material is used. The minimum size for an active pile is 3’ x 3’ x 3’. The pile is now finished. You do not need to add a compost activator because the materials have enough microbes to start the decomposition process. A properly constructed pile should reach over 100 degrees in the center within 24 hours.

Within a week you will notice that the pile has shrunk to about half the size that is was. This is due to the microbial action and compaction. In order to keep the action going, you need to periodically turn the pile and add additional water. Turn the pile so that the outside materials become the interior part of the pile. The two most important requirements for decomposition microbes are air (provided by periodic turning or aeration) and water. In our dry climate, insufficient water is usually the reason that a compost pile is not active. An active composting system should have temperatures between 90 to 140 degrees in the pile center. Continue turning or aerating the pile every four to seven days until the compost is finished to your liking (thoroughly composted for a soil additive or partially composted to use as a mulch).

Problems that you may encounter with the pile are:
• Smells – ammonia smell due to excess nitrogen, add more brown material; rotting smell, the pile needs to be turned (anaerobic activity) or pile is too wet, add dry material
• Pile not heating up – over watering or insufficient nitrogen or turning the pile too frequently or pile is too small
• Materials not breaking down – all materials compost faster the smaller they are Compostable garden waste, brown (Carbon source) material

By Sharon Bokan, Colorado State University Extension, Boulder County. Sharon is the Small Acreage Coordinator at Colorado State University Extension Boulder
County. For more information call 303.678.6176, e-mail [email protected] or visit