Composting

Composting, nature's own way of recycling, is the controlled decomposition of organic material, such as leaves, twigs, grass clippings, and vegetable food waste.  Compost is a soil amendment product that results from proper composting techniques. Whether it's done on-site, at the point of waste generation, or in a large-scale, centralized facility, composting helps to keep the high volume of organic material out of landfills and turns it into a useful product. Large-scale facilities can handle more material and potentially produce a more consistent product, but may be faced with regulatory issues. On-site composting reduces the cost of hauling materials and is generally exempted from solid waste regulations.

Worm Composting

Worm composting can be done in the kitchen using food scraps. Click the link for further instructions and information on worm composting.

Bin/Pile Information

Composting can be practiced in most backyards using a homemade or manufactured composting bin, or simply an open pile (some cities do require enclosed bins). In addition, businesses, schools, and other facilities can also easily compost. Homemade bins can be constructed out of scrap wood, chicken wire, snow fencing or even old garbage cans (with holes punched in the sides and bottom).

Manufactured bins include turning units, hoops, cones, and stacking bins. These can be purchased from retail or mail order businesses. Many municipalities have compost bins available for purchase at a subsidized rate.

Check with the Los Angeles County Smart Gardening Program at www.smartgardening.com or (888) CLEANLA.

Biostack compost bin

Ingredients

While a multitude of organisms, fungus and bacteria are involved in the overall process, there are four basic ingredients for composting: nitrogen, carbon, water and air. Composting is a lot like cooking, and the easiest compost recipe calls for blending roughly equal parts of green or wet material (which is high in nitrogen) and brown or dry material (which is high in carbon). Simply layer or mix these materials in a pile or enclosure, chop or shred large pieces to 12" or shorter, water, and fluff materials to add air. Then leave it to the microorganisms to decompose the material over time.

Nitrogen
Green materials, such as grass clippings and landscape trimmings, are ideal sources of nitrogen for composting. Vegetable and fruit trimmings can also provide nitrogen. To reduce the potential for pests or odors, it is best to: 1) avoid meat or dairy scraps and 2) bury any food scraps deep within the compost pile.

Carbon
Brown (dry) yard and garden material, such as dry leaves, twigs, or hay, can provide the carbon balance for a compost pile. Chop or shred large pieces to 12 inches or shorter (thick, woody branches should be chipped, ground up, or left out). Untreated wood chips and sawdust are a powerful carbon source that may be useful if the pile contains excess nitrogen.

Water
One of the more common mistakes in composting is letting the pile get too dry. A compost pile should be as moist as a wrung-out sponge. Moisture content of 40 to 60 percent is preferable. To test for adequate moisture, reach into your compost pile, and grab a handful of material, squeeze it, if a few drops of water come out, it probably has enough moisture, if it doesn't, add water. When watering, it is best to put the hose in the pile. During dry weather, you may have to add water regularly. During wet weather, cover the pile. A properly constructed compost pile will drain excess water and should not become soggy.

Air
The bacteria and fungus in the compost pile need oxygen to live and work. If the pile is too dense or becomes too wet, the air supply will be cut off and the beneficial organisms will die. Decomposition will also slow down and an offensive odor may arise. To avoid this and speed the process, turn and fluff the pile with a pitchfork weekly.

Size

Ideally, the compost pile should be at least three feet wide by three feet deep by three feet tall (one cubic yard). This size provides enough food and insulation to keep the organisms warm, happy, and working hard. However, piles can be larger or smaller and work just fine if managed well.

Composting Techniques

Composting can be done "gourmet" style, requiring more effort, with quick results--or can be done more casually. Both ways will have a positive effect on the environment and produce usable compost.

"Gourmet" compost piles that have the right blend of nitrogen (greens) and carbon (browns) and are kept moist and fluffed regularly, will heat up to temperatures of 120 to 170 degrees Fahrenheit. The high temperature will kill most weed seeds and speed up the decomposition process so that the compost may be ready in 2 to 3 months or less.

"Casual" compost piles are also quite workable since compost will "happen" even if you just pile on yard and food waste, water sporadically, and wait. The pile won't get as hot, so it won't decompose as quickly and may not kill weed seeds. Casual composting can take several months.

For more information:

Check with the Los Angeles County Smart Gardening Program at www.smartgardening.com or (888) CLEANLA.

How to Tell When it's Done
Your compost is finished when the original material has been transformed into a uniform, dark brown, crumbly product with a pleasant, earthy aroma. There may be a few chunks of woody material left; these can be screened out and put back into a new pile. You may want to stop adding to your compost pile after it gets to optimal size (see above) and start a new pile so that your first pile can finish decomposing (during which time the temperature will drop).

Give it a Try!

Home composting is best learned by doing. There are a number of books written on backyard composting; check your local library or bookstore. Also check with your local government for workshops, handouts, or guides on composting.

For more information:

California Integrated Waste Management Board - http://www.ciwmb.ca.gov/Organics/Gardening/

Master Composters - http://www.mastercomposter.com

Cornell University - http://compost.css.cornell.edu/Composting_homepage.html