What is considered the ideal C:N ratio for composting?

The ideal carbon-to-nitrogen (C:N) ratio for composting is typically around 25:1. This ratio is considered optimal because it promotes efficient microbial activity, leading to faster decomposition of organic materials. Microorganisms responsible for composting need both carbon, which serves as an energy source, and nitrogen, which is necessary for their growth and reproduction.

When the C:N ratio is balanced at approximately 25:1, the microorganisms can efficiently break down the organic matter, resulting in a hot, aerobic environment that speeds up the composting process and produces high-quality compost. A ratio that is too high in carbon (such as 35:1 or higher) can lead to slower decomposition and potentially anaerobic conditions, while a ratio that is too high in nitrogen can produce unpleasant odors and excess moisture. Thus, the 25:1 ratio is widely accepted as the optimal point for both effective composting and quality of the resulting compost product.