Compost Calculator

By volume, aim for roughly 3 parts brown (carbon-rich: dried leaves, cardboard, straw) to 1 part green (nitrogen-rich: food scraps, grass clippings, coffee grounds). By weight, the ideal carbon-to-nitrogen ratio is about 25-30:1, which the 3:1 volume ratio approximates.

Hot composting with regular turning: 4-8 weeks. Cold composting (passive pile): 6-12 months. Tumbler: 3-6 weeks. Factors that speed it up: smaller pieces, correct moisture (like a wrung sponge), regular turning, and the right brown/green ratio.