Did you know the Environmental Protection Agency estimates consumers in the United States generate over 4 pounds of trash per day on average? That’s nearly 1,500 pounds each year. Even more stunning is how much of that waste is food. Nearly one third of our food — ranging from leftovers to spoiled produce — is uneaten, and 96% of that ends up in landfills. Even if we try to reduce food waste by planning better and modifying habits, we will still generate food scraps at home.
The best way to keep food out of landfills is to compost it. Composting involves the biological decomposition of organic materials to form a humus-like substance valued by gardeners everywhere. Although decomposition occurs naturally, it can be accelerated by controlling environmental factors to achieve the proper balance of carbon-rich and nitrogen-rich materials, oxygen, and water. Carbon-rich materials are dry and brown, such as leaves, straw, wood, shredded cardboard, or paper. Nitrogen-rich materials are wet and green — think fresh grass clippings and food waste. The optimal ratio is 25 to 35 units of carbon to one unit of nitrogen. Oxygen, which is affected by wind, moisture content, and porosity, can be provided by turning the compost pile regularly. Water can be added as needed.
Most decomposition happens because microorganisms like bacteria, fungi, and actinomycetes change the chemical composition of wastes. Mites, centipedes, sow bugs, snails, beetles, slugs, ants, and earthworms are the most common visible decomposers. They grind, bite, tear, and chew materials into smaller pieces. But we can’t see the most important decomposers — aerobic bacteria — even though there may be millions in a gram of soil or decaying organic matter.
Bacteria eat a variety of organic compounds but need a favorable environment — oxygen, moisture, and temperature — to create compost. As bacteria gain energy from eating, the compost pile heats up. If it gets too hot, or lacks oxygen or moisture, the bacteria could die or become inactive. This is why people monitor conditions of their compost piles. Temperatures between 130 and 160 degrees are ideal, but it’s not necessary to measure temperatures. If the pile isn’t heating up, add greens and turn it. When it stops heating up and there aren’t any visible food scraps, let it cure for a month. Compost in a well-maintained pile looks dark, loose, and crumbly and smells like fresh soil.
Worm composting (vermicomposting) is a method requiring little space, but more attention. It’s sort of like acquiring a new pet — worms need a container, water, food, and regular monitoring.
Composting doesn’t just divert waste from landfills; it saves money. Use compost as a soil amendment or mulch. Your soil will retain more moisture and nutrients and attract beneficial organisms, which will reduce the need for pesticides. Since many communities have ordinances regulating composting, contact your local government.
Master gardener Vicki Spencer has an eclectic background in conservation, water, natural resources, and more.