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Create perfect compost with our calculator. Determine the optimal ratio of green (nitrogen-rich) and brown (carbon-rich) materials for fast, healthy decomposition and nutrient-rich compost.
9.0:1
Needs adjustment (target: 25-30:1)
Add approximately 44.8 lbs of brown materials (dry leaves, cardboard, straw) to increase carbon.
Fast but may smell due to excess nitrogen
Tips:
Below 25:1: Too much nitrogen, may smell, decompose too fast
25-30:1: Optimal balance for efficient composting
Above 30:1: Too much carbon, slow decomposition
Composting transforms kitchen scraps and yard waste into nutrient-rich soil amendment, reducing landfill waste while creating "black gold" for your garden. The key to successful composting is balancing carbon-rich brown materials with nitrogen-rich green materials. Our compost calculator helps you achieve the ideal 25-30:1 carbon-to-nitrogen ratio for efficient decomposition.
Browns (high carbon) include dried leaves, straw, paper, cardboard, and wood chips. Greens (high nitrogen) include fresh grass clippings, vegetable scraps, coffee grounds, and fresh plant material. Too much carbon slows decomposition; too much nitrogen creates ammonia smell and attracts pests. The ideal ratio creates hot compost (130-150°F) that decomposes quickly (4-8 weeks) and kills weed seeds and pathogens.
Beyond C:N ratio, successful composting requires moisture (like a wrung-out sponge), oxygen (turn pile weekly), and particle size (smaller pieces decompose faster). Browns provide structure and air pockets; greens provide nitrogen for microbial activity. Layer materials or mix thoroughly, keep pile moist but not soggy, and turn regularly to introduce oxygen.
Our calculator includes 14 common materials with their C:N ratios, making it easy to balance your pile. Start with roughly equal volumes of greens and browns, then adjust based on our recommendations. Finished compost is dark brown, crumbly, and smells earthy. Use it to improve soil structure, retain moisture, suppress disease, and provide slow-release nutrients. Composting closes the nutrient loop, turns waste into resource, and builds soil health naturally.
Bad smell indicates too much nitrogen (greens) and insufficient oxygen. Add browns (dried leaves, shredded paper), turn pile to introduce oxygen, and ensure it's not too wet. Properly balanced compost smells earthy, not putrid. Ammonia smell means too much nitrogen.
Not recommended for home compost—these attract pests and create odors. Stick to plant materials, coffee grounds, eggshells, and paper. Commercial compost facilities can handle these materials at high temperatures, but home systems can't reliably kill pathogens or prevent animal intrusion.
Hot composting (proper C:N ratio, regular turning, adequate moisture) produces finished compost in 4-8 weeks. Cold composting (pile it and forget it) takes 6-12 months. Factors affecting speed: particle size, C:N ratio, moisture, oxygen, temperature. Smaller pieces and proper ratios speed decomposition.