In Oklahoma, yard trimmings and grass clippings can make up 15 to 25 percent of a community’s waste, according to OSU consumer horticulture specialist David Hillock. The costs of collecting and transporting yard waste and the subsequent landfill fees may be a considerable portion of a community’s waste management budget. Hillock says these costs may be reduced if homeowners and gardeners practice backyard yard waste composting.
Yard wastes, especially grass clippings, are usually high in nutrient content. When yard waste is composted, bacteria use air and water to break down plant materials into nutrient-rich compost. These nutrients can be beneficial to soils, plants, and trees in the yard when applied as mulch or a soil amendment.
Compost systems can be simple and slow as a heap or pile, which is turned occasionally during the year. A more structured and complex system requires containers, more turning, and produces finished compost in a few months. In compost piles, water is added to green and brown vegetation layers.
As decomposed plant material, compost is an excellent soil amendment. Compost can loosen clay soils, help sandy soil retain moisture and nutrients, and retain soil moisture when used as mulch. Beneficial bacteria and organisms in compost assist plants in absorbing nutrients. Thus, natural materials are recycled in a home yard environment.
Compost is a natural dark brown humus-rich material formed from the decomposition or breakdown of organic materials such as leaves, grass clippings, vegetation, vegetable food scraps, and twigs. Bacteria, worms, fungi, and insects need water and air to use the organic materials as food and decompose them.
To make compost, organic materials are placed in alternating green and brown layers in a container, bin, or pile. Alternating green and brown layers of material help assure the correct carbon and nitrogen amounts. With water and air, bacteria and insects use the materials as a food and energy source. The bacteria need water to live and grow. This process generates heat from 140 to 160 degrees F. Aeration is done by turning the container or pile of material. The more turning, the more air the bacteria have available, and the faster the process works. When the temperature decreases, the process is complete.
Compost bins may be made in various sizes and with a variety of materials. The following easy steps describe compost pile construction:
1. Construct a confining perimeter with 3’ to 5’ diameter and 4’ high. Materials may be concrete blocks, railroad ties, wire mesh, boards, old pallets, other fencing material, barrel, or garbage can with holes for air
2. Layer green (wet) and brown (dry) vegetable matter (1 part green to 3 parts brown)
3. Wet thoroughly, then sprinkle with water periodically
4. Turn every week to speed the decomposition process
The time for completion of finished compost will vary according to the type and amount of materials used, the climate, the size and type of bin or pile used, and the amount of aeration or turning of the pile. With the correct carbon to nitrogen ratio, water, and air, compost should be ready to use in 4-6 months. If the pile is turned more frequently, the compost should be ready more quickly. The smaller the individual pieces of material in the pile, the more surface area the microorganisms have to work on and the faster the materials will decompose. Shredding or chipping branches decreases the decomposition time.
Compost is ready when the temperature of the pile falls to ambient levels, the material is dark, crumbles easily, pieces are small and there is no odor. Mixing frequently speeds up the composting time by providing more air for the bacteria. Keep the material moist with soaking about once a week.
A wide variety of organic wastes can be composted, including: most yard waste (such as grass clippings, leaves, and twigs), non-fat containing food scraps, twigs or chipped branches, coffee grounds and tea leaves.
Things that should not be composted include: large branches, fatty foods, grease, meats, dairy products, fish, bones, synthetic products such as plastics, diseased plants, weeds, vegetables that produce abundant seeds and pet or human waste.
There are a lot of good reasons to compost besides saving landfill space. Composting allows for reduction in the use of commercial fertilizers, saves money on fertilizer and waste disposal costs, improves water and air penetration into the soil, and is a natural recycling method.
Finished compost can be used to improve soil structure and texture, increase water-holding capacity of sandy soil, loosen clay soil and improve drainage, add nutrients to improve soil fertility, aid in erosion control, make potting soil and mulch around shrubs to retain moisture.
Compost bins, either homemade or commercially purchased can be of several different styles:
1. Garbage can or barrel – with holes in bottom and in rows about 4-6 inches around sides. These can be homemade or purchased commercially – many varieties usually about the size of a 30-gallon garbage can, found at home supply stores.
2. Three bin turning units are made so that the compostable material can be easily transported from one bin to another, thus reducing the time to produce the compost. They can be made out of a variety of materials. Some of those materials are concrete blocks, wood with wire sides, and wood slats (such as old wood pallets).
3. Holding units (for easy passive composting) can be made from many materials, require no turning and are thus slower to produce compost. Some of these products include wood pallets, concrete blocks, chicken (or other type) wire and snow fence.
More information on backyard composting is available in OSU Extension Fact Sheet HLA-6448, “Backyard Composting in Oklahoma”.
If you have any questions, or would like further information on this or other related management topics, visit us on the west end of the Clay Jones Community Building at 1901 S. 9th Avenue in Durant, or call (580) 924-5312.
The Oklahoma Cooperative Extension Service offers its programs to all eligible persons regardless of race, color, national origin, religion, sex, age, disability, or status as a veteran, and is an equal opportunity employer.
June 16-17 – Golden Harvest Days, Esbenshade Farms. Free Admission. For more information contact Jim at (580) 283-3453 or Clay at (580) 916-2414
Robert Bourne is a Bryan County Extension Educator.