Last updated: March 2, 2026 by Dr. David Park

Understanding Composting and the C:N Ratio

Formula

Successful composting depends on maintaining an optimal carbon-to-nitrogen (C:N) ratio of about 25:1 to 30:1. Carbon-rich 'browns' (leaves, paper, straw) have C:N ratios around 50-80:1, while nitrogen-rich 'greens' (food scraps, grass) are around 15-25:1.

When the ratio is right, microorganisms decompose materials efficiently, generating heat that kills pathogens and weed seeds. Too much carbon slows decomposition; too much nitrogen causes odor and nutrient loss.

Common use cases:

  • Home composting optimization
  • Community garden waste management
  • Reducing landfill waste

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Dr. David Park

Applied Mathematician, PhD Mathematics

David holds a PhD in Applied Mathematics from MIT. He has published research on numerical methods and computational algorithms used in engineering and scientific calculators.

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