Definitions for "BROWNS"
The term "browns" is used to denote organic materials high in carbon, more specifically, materials whose carbon to nitrogen ratio is higher than 30:1. (Materials high in nitrogen are referred to as "greens"). Achieving a carbon-to-nitrogen ratio of about 30:1 is one factor in creating favorable conditions for backyard pile composting.
a type of food for composting microbes. It is dry, dead organic plant matter, such as straw, autumn leaves, and sawdust. Browns provide the sugars that the microbes need.
carbon rich compostable materials. Usually dry as well.