   Got Compost? - February 19, 2003 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Composting is a perennial subject in this column and I feel like a periodic reminder may motivate would-be gardeners to get with the program. Maybe I'm getting cynical as I age, but in my opinion, you are not a real gardener unless you compost. Composting does not smell bad, attract vermin, or take too much time. It also utilizes waste materials that would otherwise occupy space in a landfill. Composting is a microbial process that converts plant materials such as grass clippings, leaves, and kitchen scraps into a beneficial organic soil amendment. Gardeners have used compost for centuries to increase soil organic matter, improve soil physical properties, and supply some of the essential nutrients for plant growth. Composting is an art and science. The "science" is well documented and resources are available at public libraries and on the Internet (some good web sites are listed below). The "art" is making it practical and easy given your individual household, landscape, and gardening interests. If you only have a few annual flowerbeds and do not vegetable garden, you can compost kitchen scraps and yard wastes on a small scale. If you are vegetable gardener, you should make enough compost to cover the soil three to six inches deep every year. The critical factors in composting are maintaining: 1) a 20:1 carbon:nitrogen ratio; 2) good aeration; and 3) adequate moisture. You should never add human/dog/cat waste, meat products, bones, dairy products, oil, or grease to your compost. The trickiest part is the carbon:nitrogen ratio. Green wastes and manure contain relatively large amounts of nitrogen. Straw, pine needles, twigs, sawdust, wood shavings, and other non-green materials are almost entirely carbon. When the carbon:nitrogen ratio is near 20:1, the compost will get warm and smells like silage or earthy fungi. This ratio is ideal for decomposing bacteria and fungi. They utilize the carbon and nitrogen by incorporating it into their cell structure, increasing their populations and speeding the decomposition process. When there is too much carbon, compost just sits there and does not decompose. When there is too much nitrogen, the compost will smell like ammonia. You can add appropriate materials at any time to adjust the ratio and shift the activity. Adequate aeration ensures that aerobic conditions can predominate. A lack of aeration can create anaerobic conditions which leads to a stinky, unsavory compost pile. Straw, twigs, shavings can increase aeration or a few pieces of 4 inch perforated drainage pipe can be buried in the pile. Moisture is relatively easy to maintain once adequate aeration is achieved. Compost should be kept as moist as a wrung-out sponge. In humid areas, compost gets too wet and bins are designed to dry out quickly. Conversely, in northern Arizona, compost tends to dry out too quickly. For this reason, I recommend a compost bin with solid (not ventilated) sides. I just have simple galvanized sheet metal bins in my garden. For more composting information, I provide the following web sites. The University of Minnesota at: www.extension.umn.edu/distribution/horticulture/DG3296.html; Cornell University at : www.cfe.cornell.edu/compost/Composting_Homepage.html; Texas A&M at: aggie-horticulture.tamu.edu/extension/compost.html; and Ohio State University at: ohioline.osu.edu/hyg-fact/1000/1189.html. All are excellent resources for home composting. Note: the Yavapai County Cooperative Extension Web Site has been updated to include a Forest Health Page. The page focuses on bark beetles and includes two downloadable fact sheets and a page with frequently asked questions about bark beetles. Check it out at: ag.arizona.edu/yavapai/. The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://ag.arizona.edu/yavapai/anr/hort/byg/. |