Successful composting relies on keeping a number of factors in balance to allow natural biological processes of decay to work and be accelerated. Compost is created by the actions of microbial organisms metabolizing the organic material you put into the compost pile and breaking them down into their component elements. Key factors to support these processes are: maintaining a balance of dry and brown with green and moist input materials, maintaining moisture in the pile and by aerating the pile by frequently turning.
Balance of Input Materials
Composting works most efficiently when carbon-rich and nitrogen-rich organic inputs are put onto the compost pile in equal volumes and in thin alternating layers. Carbon-rich materials are typically dried and/or brown elements such as dried leaves, straw, shredded newspaper or wood shavings. Nitrogen-rich elements are typically the moist and/or green inputs such as fresh grass clippings, green leaves, flower heads, used coffee or tea grounds, fruit and vegetable peels.
Air Circulation Through the Pile
The center of the compost pile heats up significantly during the composting process which speeds the breakdown of materials. Frequent turning or churning of the pile moving the material in the center up and out and new material into the center produces finished compost more quickly. Turning also oxygenates the pile and reduces or eliminates any build-up of foul odors in the pile. Turning should ideally be done once every three to five days to keep the breakdown process at peak activity.
Water is needed in the composting process to continue the microbial activity. Green nitrogen-rich inputs bring some moisture to the pile but applied water is almost always required to keep the pile lightly and evenly moist. Adding a few pints or more of water each time a significant amount of new material is added will keep the pile moist and the breakdown process active.