Mulch
 
Definition:
From Wikipedia, the free encyclopedia.
 
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.
 
Application:
Mulch is used for various purposes:
  • To adjust soil temperature by helping soil retain more heat in spring and fall , and by keeping soil cool and evening out temperature swings during hot and variable summer conditions
  • To control weeds by blocking the sunlight necessary for germination
  • To retain water by slowing evaporation
  • Custom stenciling and branding of pallets
  • To add organic matter and nutrients to the soil through the gradual breakdown of the mulch material
  • To repel insects
  • To incrementally improve growing conditions by reflecting sunlight upwards to the plants, and by providing a clean, dry surface for ground-lying fruit such as squash and melons.
A variety of materials are used as mulch:
  • Organic Residues - grass clippings, leaves, hay, straw, sawdust, wood chips, shredded newspaper, cardboard, wool, etc. Many of these materials also act as a direct composting system. There are many differing opinions on what to use.
  • Compost - This relies on fully composted material, where potential weed seed has been eliminated, or else the mulch will actually produce weed cover.
  • Plastic Mulch - Crops grow through slits or holes in thin plastic sheeting. This method is predominant in large-scale vegetable growing, with millions of acres cultivated under plastic mulch 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.
  • To add organic matter and nutrients to the soil through the gradual breakdown of the mulch material.
  • Rock and gravel can also be used a mulch. In northern climates the heat retained by rocks will extend the growing season.
The way a particular organic mulch decomposes, and reacts to wetting by rain and dew, determine in great degree its effectiveness. Organic mulches can rot rapidly rather than slowly break down, and it can mat into a barrier that blocks water and air, both conditions that can be detrimental to crops.
 
Living mulch may also be considered a type of mulch, or as a mulch-like cover crop . This technique involves undersowing a main crop with a fast-growing cover crop that will provide weed suppression and other benefits associated with mulch.
 
Mulching is an important part of any no-dig gardening regime, such as practiced within permaculture systems.