The proportion of carbon-rich and nitrogen-rich materials in a composting system that supports efficient decomposition.
The microbes responsible for breaking down organic matter need both carbon and nitrogen. Carbon provides energy, while nitrogen supports growth and reproduction.
A healthy compost pile contains a mix of carbon-rich materials, often called "browns," and nitrogen-rich materials, often called "greens." When these materials are balanced, decomposition happens more quickly and produces high-quality compost.
If there is too much carbon, decomposition slows. If there is too much nitrogen, the pile may become overly wet, develop odors, or lose nutrients.
The right carbon-to-nitrogen balance helps compost break down efficiently and creates a nutrient-rich finished product. Understanding this balance allows gardeners to troubleshoot common composting problems and make better use of leaves, grass clippings, food scraps, manure, and other organic materials.