Compost is a common name for humus, which is the result of the decomposition of organic matter. Decomposition is performed primarily by microbes, although larger creatures such as worms and ants contribute to the process. Decomposition occurs naturally in all but the most hostile environments, such as buried in landfills or in extremely arid deserts, which prevent the microbes and other decomposers from thriving.

Composting is the controlled decomposition of organic matter. Rather than allowing nature to take its slow course, a composter provides an optimal environment in which decomposers can thrive. To encourage the most active microbes, the compost pile needs the proper mix of the following ingredients:

• Carbon
• Nitrogen
• Oxygen (air)
• Water

The ecosystem in a compost pile is a microcosm of larger ecosystems. The correct environment must be maintained for a healthy and vigorous community of decomposers. In addition to the decomposers that work directly on the organic content of the pile, compost piles provide habitat for those that prey upon direct decomposers. Their waste also becomes part of the process.

The most effective decomposers are bacteria and other microorganisms. Also important are fungi, molds, protozoa, and actinomycetes--which is something between a fungus and a mold and is often seen as white filaments in decomposing organic matter. At a macroscopic level, earthworms, ants, snails, slugs, millipedes, sow bugs, springtails, and others work on consuming and breaking down the organic matter. Centipedes and other predators feed upon these decomposers.

The goal in a compost pile is to provide a healthy environment--and nutrition--for the rapid decomposers, the bacteria. The most rapid composting occurs with the ideal ratio--by dry chemical weight--of carbon to nitrogen, from 25-to-1 to 30-to-1. In other words, the ingredients placed in the pile should contain 30 times as much carbon as nitrogen. For example, grass clippings average about 19-to-1 and dry autumn leaves average about 55-to-1. Mixing equal parts by volume approximates the ideal range.

High-carbon sources provide the cellulose needed by the composting bacteria for conversion to sugars and heat.

High-nitrogen sources provide the most concentrated protein, which allow the compost bacteria to thrive.

Some ingredients with higher carbon content:

• Dry, straw-type material, such as cereal straws
• Autumn leaves
• Sawdust and wood chips
• Some paper and cardboard (such as corrugated cardboard or newsprint with soy-based inks)

Some ingredients with higher nitrogen content:

• Wilted green material (usually crop residues, or plants mowed for the purpose)
• Animal manures (vegetarians, not meat-eaters)
• Grass clippings
• Fruit and vegetable trimmings, skins, and waste

Types of Compost Bins:

• Wooden Compost Bin - These can be bought in kit form and must be assembled. They side are slotted to allow air circulation. The fornt panellifts out.
• Plastic Barrel - Large plastic drums with the top and bottom cut off make a good compost containers. Drill holes inthe sides for air flow.
• Wire and Post - Four posts wrapped with chciken wire works well. Tie burlap to the inside if the wire to keep everything in.