Compost is the stable organic material remaining at the end of decomposition. Completed compost should smell sweet like soil, and be stable in temperature.
Often the term “compost” will be erroneously confused with “food scraps” or “kitchen scraps.” Food scraps, leaves and other organic material are technically not “compost” until they gone through a complete decomposition process.
Compost is produced one of two ways, aerobically or anaerobically. In nature, anaerobic (without oxygen) decomposition only occurs deep underwater although industrial-scale decomposition is often done anaerobically. Aerobic (with oxygen) composting is usually preferable for the home scale.
Mind your Numbers
Good compost must be produced with a proper nitrogen to carbon ratio. Most food scraps from the home and garden are very rich in nitrogen, so supplemental carbon sources must be added to make the best finished product.
How Compost is Used
Compost is generally used to replenish fertility in a food producing system. As a plant grows, it taken nutrients from the soil around it. These nutrients can be restored by applying compost before and throughout the growing season. Garden soil which is not amended with compost can become infertile.