The Magic of Microbes
Though compost may seem like magic, it relies on little critters — either microbes or worms. As King explains, these helpers require food, air and water. “Microbes rely upon a balance of carbon and nitrogen. Carbon provides the energy source, and nitrogen is used as ‘building blocks’ to produce more microbes,” King said. Specifically, this recipe translates to 30 or 40 parts paper or leaves (carbon) per one part food scraps or grass clippings (nitrogen). The mix must be kept moist and well aerated. If the mix is right, the microbes produce compost, carbon dioxide and water vapor. Without enough oxygen or the wrong mix, it could start producing stinky volatile organic acids.
Time and Temperature: The Keys to Compost
King recommends taking the temperature of a compost pile. The goal is temperatures above 120 degrees Fahrenheit. Richard Stehouwer is an associate professor of environmental soil science at Penn State University. He explains why cooler compost isn’t doing its job. “Anaerobic decomposition is much slower and generates far less heat than aerobic decomposition,” he said. “So heat dissipates from the pile as quickly as it is being generated and the pile temperature does not increase. In these systems anything that prevents oxygen from reaching zones in the pile where decomposition is ongoing will result in anaerobic conditions and production of malodorous gasses.”
“Optimizing the recipe will create an odor-free, aerobic environment,” King said. “When any of these items are out of balance, odors ensue. The good news is that with proper attention, most problems are easily fixed and odors go away.”