In composting, what is the difference between "greens" and "browns"?

• A. Greens are nitrogen-rich materials; browns are carbon-rich materials.
• B. Greens are carbon-rich materials; browns are nitrogen-rich
• C. Greens are always dry; browns are always wet
• D. Greens are for soil structure; browns are for moisture

Answer: (A)

Balancing carbon and nitrogen inputs drives effective composting. Greens are nitrogen-rich materials that are usually moist and soft—think fresh grass clippings, fruit and vegetable scraps, coffee grounds, and fresh manure. Browns provide carbon and are typically dry and woody—such as dried leaves, straw, shredded paper, or cardboard. This distinction matters because microbes need nitrogen to build proteins and energy from carbon; mixing greens and browns helps achieve a favorable carbon-to-nitrogen ratio, around 25–30:1, which promotes active decomposition and reduces odors. If the pile gets soggy or smelly, add browns to absorb moisture and increase structure; if it’s too dry or slow to decompose, add greens for moisture and nitrogen.