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Composting for Beginners: C:N Ratios, Methods & Calculator Guide

Composting for Beginners: C:N Ratios, Methods & Calculator Guide Successful composting requires a carbon-to-nitrogen (C:N) ratio between 25:1 and 30:1, a minimum pile size of 3x3x3 feet (1 cubic yard), and internal temperatures of 131-170F for hot composting. Get the ratio wrong and your pile either smells (too much nitrogen) or sits inert for months (too much carbon). Nature runs on ratios -- learn them, and your compost practically makes itself. A homeowner I worked with dumped 200 lbs of grass clippings into a 4x4x3-foot bin with no brown material. The C:N ratio was approximately 20:1 -- too nitrogen-heavy. Within 48 hours the pile went anaerobic: slimy, foul-smelling, attracting flies. He tried turning it, but without carbon sources, it re-compacted immediately. The fix cost him a weekend and a truck bed full of dry leaves: add 150 lbs of leaves (C:N 60:1) and shredded cardboard (C:N 350:1) to bring the...