In agriculture and gardening, mulch is a protective cover placed over the soil, primarily to modify the effects of the local climate. A wide variety of natural and synthetic materials are used.

Mulch is used for various reasons:

A wide variety of materials are used as mulch:

  • organic residues - grass clippings, leaves, hay, straw, sawdust, wood chips, shredded newspaper, etc. In general, these in part act as a direct composting system. There are many differing opinions on what to use. Organic mulches are usually piled to an initial height of several inches.
  • compost
  • plastic sheeting - Crops grow through slits. This method is more or less universal in large-scale vegetable growing, with millions of square feet of plastic mulch used worldwide each year. (Disposal of plastic mulch is cited as an environmental problem.)
  • organic sheet mulch - Various products developed as a biodegradable alternative to plastic mulch.