The word compost is derived from two Latin words meaning “together” and “to bring.” In one sense, it involves bringing together waste materials to ultimately form a single uniform humus. In the technical sense, composting results in the microbial decomposition of organic wastes under controlled conditions.
In Alabama, a family of four generates an average of 2.5 tons of garbage per year. Nearly a half ton of that garbage is yard waste that can be composted. Following are tips and facts about backyard composting.
- Biodegradability—the potential for being converted into simpler structures.
- Aeration—contact with air by turning so microbial aerobic metabolism takes place.
- Leachate—liquid that drains from the mix of fresh organic matter.
- Composting tools are designed to penetrate the pile and open up a passage for air and moisture when withdrawn. Tools are available from seed and garden product suppliers.
- The 130°F to 150°F temperatures generated in the core of a compost pile are adequate to kill most weed seeds and
many pathogenic organisms.
- DON’T compost fats: butter, bones, cheese, chicken, fish, lard, mayonnaise, meat, milk, peanut butter, salad dressing, sour cream, vegetable oil, yogurt.
- Sawdust will decompose very slowly unless nitrogen is added. Add 3.5 pounds of actual nitrogen to each cubic yard of sawdust, or add 11 pounds of ammonium nitrate.
- Finished compost contains nitrogen, phosphorus, and potassium, although the amount of each element varies. Most of the nitrogen and phosphorus are present in an organic form, and they are released gradually. That makes compost a good
slow-release fertilizer for trees and shrubs. Generally, additional fertilizer will have to be added for vegetables and bedding plants.
- Compost kitchen scraps, including apples, cabbage, carrots, celery, coffee grounds, egg shells, grapefruit, lettuce, onions, oranges, pears, pineapple, potatoes, pumpkins, squash, tomatoes, turnips—just about any vegetable waste.
- Compost tilled into a sandy soil improves the soil’s capacity to hold water and nutrients. Added to a heavy clay soil, compost increases the air spaces between clay particles, which improves drainage and increases soil aeration. In either soil extreme, plants benefit.
- Water is needed for the micro-organisms that decompose waste to grow and multiply. A handful of compost should feel like a wrung-out sponge. Squeeze it and no more than a drop or two should come out.
- Yard wastes—grass clippings, leaves, weeds, and prunings less than 6 inches in diameter from residences or businesses.
Compost is finished or stable—ready to use—when most of the original plant materials are not recognizable. Finished compost is dark colored, crumbly, and looks and feels like soil.
- A 1,000-square-foot area of lawn can generate up to 500 pounds of grass clippings in a single growing season.
Using Finished Compost
Compost can be used to improve soil aeration and structure, add nutrients to garden soil, and hold water and nutrients in sandy soils. Compost can also be used as a mulch to conserve soil moisture, suppress weeds, prevent crusting of the soil surface, and buffer soil temperatures.
Composting is an inexpensive and ecologically sound way to recycle yard and garden wastes, improve your soil, cut down on waste disposal costs, and save considerable space in our bulging landfills.
For more detailed information on this topic, see Backyard Composting, ANR-0638.
Kerry Smith, Extension Horticulture Associate and Alabama Master Gardener Program Coordinator; Jim Donald, Extension Biosystems Engineer, Professor; Bill Goff, Extension Horticulturist, Professor; Dave Williams, former Extension Horticulturist; and Tony Glover, County Extension Coordinator
Reviewed May 2022, Backyard Composting Tips, ANR-0638-A