Mulch is a protective cover placed over the soil to retain moisture, reduce erosion, provide nutrients, and suppress weed growth and seed germination. Mulching in gardens and landscaping mimics the leaf cover that is found on forest floors. Materials used as mulches vary and depend on a number of factors. Use takes into consideration availability, cost, appearance, the effect it has on the soil — including chemical reactions and pH, durability, combustibility, rate of decomposition, how clean it is — some can contain weed seeds or plant pathogens.
to calculate how much mulch you will need.