Composting is a biological process in which plant material, such as leaves and grass clippings, and other sources of organic matter decompose into humus, a dark brown, crumbly mass resembling rich garden soil. The resulting compost can be applied as a soil amendment, top-dressing, or mulch. Autumn, when many fallen leaves are available, is a handy time to start a compost pile, although it can be done any time of year.
When we make compost, we are doing exactly what nature does all the time by recycling valuable nutrients for reuse. The work of decomposition is done by bacteria, fungi, and other microorganisms, helped by earthworms, insects, and a variety of small creatures. For the home gardener, composting offers not only a way to improve soil but the opportunity to recycle yard and kitchen wastes while avoiding the expense and effort of disposing of these materials.