How to Compost
What do I use for a compost bin?
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. Take the time to consider your options and then select a bin that best fits your needs.
For a description of how to build your own bin, call the Home Composting Hotline at (510) 215-3021.
Recipe for Compost
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 to add air. Then leave it to the microorganisms which will break down the material over time.
Five Components of Successful Composting Nitrogen
Green materials such as grass clippings and landscape trimmings are ideal sources of nitrogen for composting. Vegetable and fruit trimmings and peels can also provide nitrogen. To reduce the potential for pests or odors, it is best to avoid meat or dairy scraps and bury any food scraps deep within the compost pile.
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 which may be useful if the pile contains excess nitrogen.
One of the most common mistakes in composting is letting the pile get too dry. Your compost pile should be moist as a wrung-out sponge.
A 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 and squeeze it; if a few drops of water come out, it's probably got enough moisture, if it doesn't, add water.
When you water, it is best to put a hose into the pile so that you aren't just wetting the top. You can also water as you are turning the pile.
During dry weather, you may have to add water regularly. During wet weather, you may need to cover your pile.
A properly constructed compost pile will drain excess water and not become soggy.
The bacteria and fungus that are in your compost pile need oxygen to live and work.
If your pile is too dense or becomes too wet, the air supply to the inside is cut off and the beneficial organisms die. Decomposition will slow and an offensive odor may arise.
To avoid this and speed the process, turn and fluff the pile with a pitchfork often, perhaps weekly. You can also turn the pile by just re-piling it into a new pile; many composting bins make this easy to do by coming apart so you can easily re-pile the old pile back into the bin.
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 and happy and working hard. However, piles can be larger or smaller and work just fine if managed well.
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. It just depends on how much time you want to spend with your compost pile and how fast you want the compost.
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 140 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.
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.
When is it 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).
Using your compost
Work into Soil. Use as a top dressing alone or with other mulching or natural fertilizer material.
Sprinkle sifted compost over lawn before watering or rainfall. Also helps suppress lawn diseases.
Shrubs, Hedges & Fruit Trees
Scatter at the driplines (not against the trunks) as a nutrient-rich mulch.
Steep a couple of tablespoons in a quart of hot water and use as a mild fertilizer (compost tea). Spread compost at the base of plants as a mulch. When potting plants, replace 1/8 to 1/4 of the potting soil with compost.
Composting is best learned by doing. Through practice and observation you will find what works best, and you can modify the process to suit your needs. There are also a number of books written on backyard composting; check your local library or bookstore.
Other ways to reduce organic waste
The pile smells bad
Problem: Not enough air; too much moisture
Solution: Turn the pile; add dry materials
The pile will not heat up
Problem: Not enough moisture
Solution: Add water
Problem: Pile size is too small
Solution: Collect more materials ad build to at least 3'x3'x3'
Problem: Lack of nitrogen-rich material
Solution: Mix in fresh manure, grass clippings, or fruit/vegetable scraps
Problem: Particle size is too big
Solution: Chip or grind materials
The pile attracts flies, rodents, or pets
Problem: Pile contains bones, meat, fatty or starchy foods
Solution: Alter materials added to pile; bury fruit/vegetable scraps in the middle of the pile