Mulch is any type of ground covering for gardens. Many people use organic mulch which is made from discomposed food or paper. Mulch usually looks nicer than regular dirt, suppresses weed growth, and is high in bacteria which discompose old growth and create nutrients for the plants your growing.

Non-organic mulch is any weed-preventing cover for a garden such as black cloth or gravel.

The purpose of using mulch is primarily to provide ground cover to prevent runoff of the topsoil during erosive weather. The topsoil is the most nutrient rich part of the soil and therefore it is important to protect it during the winter months. Mulch should not be mixed in with topsoil when planting because it actually will pull nutrients out of the soil in order for microorganisms to decompose it.