Whether choosing to go for aerobic or anaerobic compost, a number of factors are involved. Among them is that aerobic compost requires an oxygen supply while anaerobic requires limited or no oxygen. These factors determine the process followed when producing any of the two types of compost.
Composting is the natural rotting of organic matter in a controlled environment. In aerobic composting, the organic matter is piled with temperatures left to rise rapidly to about 70 to 80 degrees. This active compost stage is followed by the curing stage. This is where the temperatures are decreased gradually. In anaerobic composting, oxygen levels are limited, thus microorganisms are allowed to produce methane and other substances. Unlike aerobic composting, anaerobic compost maintains both weeds and pathogens. Therefore, anaerobic composting takes longer than aerobic composting.
One advantage of anaerobic compost is that it is less labor intensive. Consequently, unlike aerobic compost, one does not need to turn the pile. All one does is pile the material, wet the pile, cover it and allow it to sit. The pile will usually be very smelly initially. However, after some time, the aerobic bacteria will use up all the oxygen and die off. This will reduce the odor. At this point, one needs to monitor the moisture level, so that too much gas does not accumulate. This type of compost will usually be dark and slimy. This is caused by the accumulation of nitrogen and organisms that do not require a lot of energy or nitrogen to survive. The nitrogen is converted to ammonia resulting, in the smelly end result. The high amounts of heat help speed up the entire decomposition process.
Aerobic compost on the other hand requires large supplies of oxygen, more so in its initial stages. Limiting the oxygen supply results in slow decomposition. In addition, frequent aeration is essential to remove excess heat and gases that are trapped in the pile. To achieve good aeration, frequent turning of the heap is essential. The frequency of turning will determine how fast or slow the compost matures. Daily turning will ensure the entire process is complete in two weeks. If one needs the compost to mature gradually, one turn a month is adequate. When well done, both compost types are quite effective as natural forms of fertilization.