With more time at home on many people’s hands these days, lots of yard work is being tackled. Spring is a perfect time to create a home composting system.
For the new composter, first find an ideal spot on your property to locate your composting pile or receptacle, says Amanda Tedrow, a composting expert and Agriculture and Natural Resources Program Development Coordinator who represents University of Georgia Cooperative Extension's Northeast District.
Decomposition of organic material in the compost pile depends on maintaining microbial activity. Any factor that slows or halts microbial growth also impedes the composting process. Efficient decomposition occurs if aeration, moisture, particle size and nutrient levels are maintained for optimum microbial activity.
“If you are just starting out, go for the pile. The ideal minimum size for a compost pile is four by four by four (4 feet wide by 4 feet long by 4 feet deep). That is the right size to reach the temperatures needed for decomposition. A smaller pile will decompose at a slower rate due to lower temperatures,” Tedrow said.
While heat is an important element to composting, the heat is generated within the composting pile, so it is not necessary to locate a composting system in direct sun. A compost pile located in direct sun may need additional supplemental water during the heat of the summer months.
Temperature of the compost pile is important to the biological activity taking place. Low outside temperatures slow activity, while warmer temperatures speed decomposition. Microbes contributing to decomposition are mesophilic, those that live and function in temperatures of 50 degrees to 113 degrees, and thermophilic, those that thrive at temperatures between 113 degrees and 158 degrees. A well-mixed, adequately working compost pile will heat to temperatures between 110 degrees and 160 degrees as microbes feed on organic materials. High temperatures help destroy weed seeds and disease organisms within the pile.
It's important to add the right mix of materials to the pile. “The general recommendation is to do two-thirds to three-quarters browns and one-third to one-quarter greens,” Tedrow said. Brown materials — dried leaves, sticks and old mulch — are a source of carbon, while green materials — grass clippings, vegetable and fruit scraps, coffee grounds and egg shells — are sources of nitrogen, both important for proper composting. Avoid adding any kitchen waste that contains meat, dairy products or greasy substances, Tedrow warns.
Moisture is essential, but a compost pile should only stay “as wet as a wrung-out sponge,” Tedrow said. Dry compost will not decompose efficiently. Proper moisture encourages the growth of microorganisms that break down the organic matter into humus. If rainfall is limited, water the pile periodically to maintain a steady decomposition rate. If the pile should become too wet, turn it to dry it out and restart the process.
Oxygen is required for microbes to decompose organic wastes efficiently. Some decomposition occurs in the absence of oxygen; however, the process is slow, and foul odors may develop. Mixing the pile once or twice a month provides the necessary oxygen and significantly hastens the composting process. A pile that is not mixed may take three to four times longer to decompose. Raising the pile off the ground allows air to be drawn through the mass as the material decomposes. Coarse materials should be placed on the bottom as the pile is built or placed in the pile and removed after the decomposition starts.
“In an ideal world, a compost pile should be turned when the temperature in the center of the pile starts dropping (below the ideal temperature of 130 to 160 degrees). Most people don’t have a compost thermometer, so many composters will turn their pile every week to two weeks to keep the process moving,” Tedrow said. Compost thermometers are available in stores or online starting at about $20, she added.
If you have a free-form compost pile and you are having a hard time keeping compost materials together, consider using a piece of fencing or other material to make a hoop around the pile to keep it contained, Tedrow added.
While creating a compost pile can, in time, produce material usable for gardening, the best thing about a compost pile is keeping unnecessary waste out of landfills, as landscape refuse, such as leaves, grass clippings and trimmings, accounts for up to 20% of the waste being placed in landfills.
Roger Gates is the agricultural and natural resources agent for University of Georgia Extension, Whitfield County. Contact him at firstname.lastname@example.org.