Adding household waste to a compost pile or bin is more than just a way to reduce the amount of material you send to landfills. By properly managing the process, the microorganisms in a compost bin will turn organic waste into a rich, dark, soil-like material that enhances growth of gardens, flower beds or lawns. For a thriving compost pile, you need a proper balance of two kinds of material, which compost pros call "green" and "brown."
Brown for Carbon
Shredded or torn paper is considered a "brown" material. Brown materials are rich in the element carbon, an essential building block for life. In addition to paper, typical brown material includes dried leaves, woody plant stems and twigs, sawdust and straw. Other brown materials that might be surprising include natural cloth (cotton or wool), hair and dryer lint.
When adding paper scraps to a compost pile, avoid using slick paper like that found in magazines.
Green for Nitrogen
"Green" materials are higher in nitrogen than brown materials. Nitrogen, a component of amino acids and proteins, is also essential to life. Green materials include fresh grass clippings, kitchen fruit and vegetable scraps, coffee grounds and tea leaves. Eggshells are sometimes considered green, although they are neither carbon- nor nitrogen-rich.
The Compost Recipe
Aerobic bacteria and fungi in the soil naturally break down complex organic molecules into their component elements. The microbes then "recycle" the elements, recombining them as nutrients in a form plants can readily use. A compost pile speeds up this process by concentrating the microorganisms and their food in a small volume.
The decomposing microbes essential to composting seem to work best when the ratio of green to brown material is about 50:50 and the two are well-mixed. Besides carbon and nitrogen, the microbes require water and air. Regular mixing of compost by turning over the contents of the bin or pile allows air to reach the center of the pile.
A compost pile that has been "fed" the right balance of greens and browns, watered properly and regularly aerated can yield a pile of dark brown material that looks like rich soil in as little as three months. Cold weather, insufficient water or air, or a green-brown imbalance can slow the process.
What Not to Compost
Do not add meat, dairy products or pet waste (dog or cat) to your compost bin. Other items to avoid include material from diseased plants, plants treated with herbicide or pesticide, or plastic.
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