Mulch is a protective covering such as straw or leaves that is spread on the ground. Its primary function is to reduce evaporation or control weeds. It usually includes some form of plant material.
Mulch is commonly used in gardening. Mulch also often produces an odd smell which is the result of helpful bacteria decomposing plant matter. This also results in heat.
- The Merrian-Webster Concise School and Office Dictionary, Merrian-Webster Inc, 1991