Composting How to
The reason for using a verb for the title of this article is that compost is not a static thing. Compost is teeming with life, breaking down dead organic material as it uses it for energy and nutrients. Fungi break down carbon compounds, making them available to bacteria and plants. Bacteria combine nitrogen with oxygen to make other molecules that plants need to grow.
Think of a forest of deciduous trees. Think of the leaves falling in the autumn. The leaves, left to their own devices, rot, thanks to fungi and bacteria, and make rich topsoil that feeds the forest plants in the spring. Compare that to a lawn or park, where fallen leaves are considered untidy, raked up, and thrown away. What a waste.
According to the soil experts, the ideal ratio of carbon to nitrogen in compost is 30 to 1. That undoubtedly works well for those experts who have a laboratory available. For those of us who do not intend to make the stuff commercially, a more casual approach will probably fit better into our lifestyles. Let's just say that it's best to have more high-nitrogen materials than high-carbon materials.
Organic matter all has some carbon, nitrogen, oxygen, and hydrogen, but in general things like tree trunks and limbs and newspaper (made from tree trunks) are higher in carbon, and things like grass cuttings and waste from fruits and veggies is higher in nitrogen. If you are really lucky, you can obtain some chicken droppings or horse manure, which will really add some nitrogen to your compost. Some owners of livestock are generous about giving the stuff away. Some individuals getting rid of trees by cutting them down and grinding them down into fine wood chips are also happy for people to come and haul it away. If you use grass cuttings, avoid late summer and fall to gather your cuttings, since that is when grasses produce seeds. The same goes for weeds. The last thing you need in your compost is grass and weed seeds. Like other living things, fungi and soil bacteria need water to live, so keep your compost moist.
Some people put eggshells into their compost for their calcium carbonate content, which is good for raising soil pH if your soil is too acidic. Eggshells are particularly recommended for tomatoes, which like a more alkaline pH than many other veggies. The calcium is also recommended for helping tomato plants to fight off disease. Bear in mind that if your water supply is hard, it probably already contains some calcium. You can also supply eggshells to only your tomato plants by mixing them with the dirt when you plant them. In either case, smash the shells into the smallest bits you can first.
If you have enough land so that it won't show, or if you want the rustic look, you can simply make a compost pile on the ground. Commercially-produced composters are also available, designed to be neat and to allow you easily to turn and aerate your compost. The method I favor is simply to use a plastic trash can and reach inside to turn my product.
The reason we turn compost is that, when carbon compounds are broken down, carbon dioxide and heat are produced. When the compost becomes too hot and runs out of oxygen, the good microbes will die and the thermophiles, more primitive bacteria, will overgrow. The thermophiles are left over from an earlier time when the planet was hotter, and are not helpful for decomposition. When your compost heats up, use a tool such as a rake to lift the central, hottest part, to the edges, so that it will cool down and get some oxygen, necessary for the good microbes to be able to break down carbon compounds.
You will know when your compost is ready to use when it resembles dirt. Squeeze it and it will feel like rich earth. Smell the rich smell of good earth. Now go and have fun gardening.