Composting is one of the best ways you can reduce the amount of waste you are responsible for, helping wildlife, adding fertility to the soil, increasing plant health and crop yield... there are SO many good things about composting!
It is a natural process which happens to almost anything which has ever lived or grown, or come from a living organism, animal or plant, given the right conditions of adequate moisture and enough oxygen. It is also known as decomposition, rotting, biodegredation... and it always occurs because of the action of bacteria, fungi and other small organisms such as worms, woodlice, springtails and many many more.
Home composting is easy... sometimes as simple of throwing your kitchen and garden waste in a pile and letting it rot down with no management, but to keep the pile tidy, most people use a wooden or plastic bin or at least sides to the heap... and this can allow the results of the process to be harvested. This is known as compost or humus, and is a vital component of soils and growing media. The key elements of a successful compost pile are a mix of materials, moisture but not waterlogging, air but not drying out. Mixing or turning your compost pile also helps by breaking up compacted layers and adding air. The process mostly happens at ambient temperatures but if you build a big enough pile all at once, the microbial activity will cause it to warm up, and some heaps can reach 70 degrees Celsius, hot enough to kill weed seeds and sterilise manures. Some compost bin retailers, especially those selling tumblers will say things like 'makes compost in just 2 weeks'. This is nonsense. An initial (bacterial) decomposition will occur in that time, if there is a good mix of finely chopped or shredded material, but this will need to sit and let more (fungal) decomposition take place before it can really be classed as a soil improver or compost.
Many people say that they are surprised how much their pile just disappears... they throw on some kitchen waste and packaging cardboard, and next time they visit the pile, the level has gone down to the same level as before... so where has it gone? Well kitchen waste is mostly water, which drains away and evaporates, and the decomposition releases some carbon dioxide, which disappears into the atmosphere. 10kg of kitchen waste will realise less than 1kg of finished mature compost, but if woody wastes are used as well, these take longer to rot down and result in a greater amount of finished compost.
John Cossham 11:46, March 21, 2010 (UTC) (Master Composter, York, UK)