We’ve said it before and we’ll say it again, composting can be as complex or as simple as you choose to make it. If a leaf falls in the forest and no one is there to compost it…. you get the idea. Aerobic decomposition is a fundamental, natural process in nature. So why do people seem so concerned with the carbon to nitrogen ratio? This is due in part to the basic tenants of decomposition, the bacteria and microbes responsable for breaking down organic material need both of these elements to function. http://www.naturesperfectplantfood.com/2012/02/19/micro-organisms-in-vermicompost/ All aerobic decomposition requires four basic ingredients, air, water, carbon and nitrogen, this is the stuff of life. The micro organisms that drive the composting process simply function better or worse depending on the availability or the amount of each substance. For example, if deprived of moisture, microbes die off and composting halts. If too much moisture is present anaerobic microbes take over and poison the aerobic ones leading to smelly and toxic anaerobic decomp. As with all terrestrial life, aerobic organisms breathe in air and breathe out carbon dioxide. Anaerobic ones require no air and produce methane. The carbon to nitrogen ratio (C:N) refers to the organic material itself. The first chemical set free by water after a plant dies is nitrogen, once soluble the microbes can then begin to use the nitrogen to reproduce and colonise the organic material, starting the decomposition process. The Carbon is used as an “energy” source, remember we are talking about chemical interactions here. Without these base elements the actual mechanisms of life will cease.
Optimal composting is a balance of the fundamentals, the correct amounts of water and air control the temperature and speed of decomposition. Most “experts” feel a C:N ratio of 30:1 with moisture around 55% is prime. So, what materials add up to this magic number. You’ve probably heard of adding green and brown material to your composter. This is a vague reference to the C:N ratio. Green grass clippings would have a C:N much higher than dried leaves, green material has more nitrogen and less carbon. Ultimately any organic material will eventually compost and form soil, by balancing the four basics elements you can achieve this goal faster.