Autumn is not only time to rake leaves but also time to start a compost pile. Fallen leaves provide the ‘brown’ carbon-rich ingredients to the compost pile, while grass clippings from the last lawn mowing provide the ‘green’ nitrogen-rich ingredients. Compost can be ready for next spring’s plantings by following a few key steps. (These tips apply to a stationary compost pile turned by hand.)
- Do not compost everything. Nutshells, tree roots, magnolia and oak leaves, and sweetgum balls decay very slowly. Don’t add diseased plants and weeds with flowers.
- Smaller pieces decay faster than whole leaves. Before winterizing the lawnmower, use it to grind leaves.
- Provide enough nitrogen to feed the microorganisms doing the composting. The standard recommendation is equal amounts of brown and green ingredients. With grass clippings as the source of nitrogen, the ratio can be stretched to two parts leaves to one part grass. It’s OK to add a cup of general use fertilizer to supply nitrogen if there isn’t enough grass.
- Leftover compost is like sourdough starter—it jump-starts the composting process by introducing microorganisms that thrive in a compost pile. A couple handfuls of clay soil also helps the process.
- Bigger is faster, because a large pile holds heat better than a small pile. A compost pile should measure 1 yard wide by 1 yard tall (or larger).
- A compost pile needs water for microorganisms to grow. Follow the “wet as a wrung-out sponge” rule-of-thumb and imagine a wet-but-not-dripping sponge as the right amount of moisture for the pile.
- Use a thermometer to monitor compost temperature once or twice a week. Turn the pile when the temperature is dropping or stays at 80ºF for a few days. If the temperature is rising, don’t turn the pile to avoid disrupting the process.
When compost is ready is a personal preference. It takes about six months over the winter until compost reaches the fine particle stage that looks like soil. When the pieces are larger, compost can be used as mulch and topdressing. For more information on composting, see HGIC 1600, Composting.