Compost Carbon-Nitrogen Ratio

Balance green and brown compost ingredients to reach an ideal carbon-to-nitrogen ratio for fast, odor-free decomposition.

Weight of nitrogen-rich greens like kitchen scraps
Typical C:N ratio of the green material
Weight of carbon-rich browns like dry leaves
Typical C:N ratio of the brown material

Ratios are approximations; actual nutrient content varies by material.

Examples

  • 10 kg greens (17:1), 5 kg browns (60:1) ⇒ 31.33 C:N
  • 5 kg greens (20:1), 15 kg browns (80:1) ⇒ 65 C:N
  • 8 kg greens (15:1), 8 kg browns (40:1) ⇒ 27.5 C:N

FAQ

Why is C:N important?

Proper ratios speed composting and reduce odors.

Can I use volume instead of weight?

Weight is more accurate because material densities vary.

What is the ideal ratio?

Around 30:1 for efficient composting.

How often should I adjust the ratio?

Check the balance whenever adding large amounts of greens or browns.

Additional Information

  • Aim for an overall C:N ratio near 30:1 for efficient composting.
  • Greens like fruit scraps add nitrogen; browns such as straw supply carbon.
  • Mix materials thoroughly and keep the pile moist to aid microbial activity.

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