gen-define-the-carbon-to-nitrogen-ratio-in-compost-and-give-one-eb4c

Define the carbon-to-nitrogen ratio in compost and give one short worked example.

# Carbon-to-Nitrogen Ratio in Compost ## Definition The **carbon-to-nitrogen ratio (C:N ratio)** is the proportion by weight of carbon to nitrogen in organic materials used for composting. It's expressed as a ratio like 30:1, meaning 30 parts carbon to 1 part nitrogen. - **High C:N materials** (browns): dry leaves, straw, wood chips, paper (50:1 to 500:1) - **Low C:N materials** (greens): fresh grass, food scraps, manure (15:1 to 25:1) - **Ideal C:N for composting**: approximately 25-30:1 ## Worked Example **Problem:** You have 10 kg of dry leaves (C:N = 60:1) and 5 kg of grass clippings (C:N = 20:1). What is the overall C:N ratio of the mixture? **Solution:** For **leaves (60:1)**: - Carbon = 60/(60+1) × 10 kg = 9.84 kg - Nitrogen = 1/(60+1) × 10 kg = 0.16 kg For **grass (20:1)**: - Carbon = 20/(20+1) × 5 kg = 4.76 kg - Nitrogen = 1/(20+1) × 5 kg = 0.24 kg **Total C = 9.84 + 4.76 = 14.6 kg** **Total N = 0.16 + 0.24 = 0.4 kg** **Overall C:N ratio = 14.6 : 0.4 = 36.5:1** This ratio is slightly high but acceptable for composting.