Composting is the art and science of combining organic wastes in a way that they decompose into rich humus. Organic wastes suitable for composting are grass clippings, manures, leaves, sawdust and non-animal based kitchen scraps.
Composting occurs when pile temperatures are high and there is plenty of oxygen and moisture in the pile. The organisms that break the organic matter down work best at 110-130 degrees F. Warmer temperatures kill weed seeds and disease organisms, but may also slow the decomposition process. Temperatures lower than 110 degrees also slow the process.
Good airflow through the organic material is important, so a compost pile does best when turned. The more often the pile is turned when it reaches an interior temperature of 130-140 degrees, the faster the pile becomes compost. Without turning, it may take a year to have good compost.
A moisture level of 40 to 60 percent is ideal. In our arid climate, water the pile on a regular basis to keep the moisture level.
Starting the compost pile requires high nitrogen materials such as chicken manure, kitchen scraps or pesticide-free, fresh grass clippings. This is the green portion of the recipe. The next brown component is dried carbon-type material: straw, leaves, wood chips, sawdust or torn-up newsprint. A few shovels of soil add the microorganisms. Eggshells and coffee grounds are great additions. You can even compost the filters. According to Magdoff and van Es in "Building Soils for Better Crops," a good ratio is 25-40 parts brown or carbon material to 1 part green or nitrogen material. A good size for a pile is 3 feet tall and across.
When constructing a compost pile, avoid coal ash, chips from treated lumber, pet manure, animal fats. Don't include meat products or bones as they are difficult to break down and can attract critters. Branches, sticks, melon rinds and other large materials need to be broken down into smaller sizes for efficient composting.
Composting information at www.cfe.cornell.edu/compost
- JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension.