Compost occurs spontaneously in nature where the right conditions allows dead plant matter to be broken down by aerobic microbes (oxygen loving) into a soft, dark and moisture retentive material. As well as providing plant nutrients (mainly carbon and nitrogen) it also contributes to soil bulk, improves soil aeration and moisture retention, and releases beneficial microbes and invertebrates into the soil.
Gardeners speed up the composting process by tweaking the conditions of decay. The aim here is to encourage the aerobic microbes to work faster, and heat up the compost pile to 60 degrees so plant matter can breakdown. By ensuring the right balance of wet and dry plant material, making sure that material is small enough to break down, maintaining good oxygen levels and keeping the pile warm, excellent compost can be made. Composting is also encouraged by having a large amount of matter in the compost pile, the best is around 1 cubic metre.
Problems with composting generally occur when there is an imbalance of wet and dry material, or there is not enough oxygen. If your pile becomes too dry, basically nothing will happen and you’ll be left with the same pile of garden clippings you put in. If your pile becomes too wet or does not have enough oxygen, the action of anaerobic (oxygen hating) microbes will kick in, leading to your pile rotting into a slimy mess that gives of carbon dioxide.
Next post I’ll go into what (and what not) to put in our compost and how to get the best out of it.