The first takes place in the presence of oxygen, the second in the absence of oxygen. Different organisms do the decomposting work, depending on whether the conditions in the compost pile are aerobic or anaerobic. The aerobic process is generally used for home composting. The recipe for compost begins with leaves, grass, weeds organic garbage, or manure. Kept moist and aerated, a symphony of live things starts to work in the compost pile.
Bacterial activity heats the interior to destroy pathogens and larvae of harmful insects.
Species intolerant of heat work near the surface. The final product is a humus that boosts the growing power of soil. It restructures soils, allowing air and water to penetrate and aid in water retention. Compost can be produced in weeks or months, depending on the method. Moisture and air is important.