Extension Communications
Extension 4-H Youth Building
Ames, Iowa 50011-3630
(515) 294-9915
|
|
Extension Communications |
5/10/04
Contacts:
Kristy VanTilburg, Plant Health and Protection and Agronomy, kristyvt@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033,
jmcguire@iastate.edu
Yard and Garden Column for the Week Beginning May 14, 2004
Mulching - Merits and Materials
By Kristy Van Tilburg
Plant Health and Protection and Agronomy Student
Iowa State University
Mulch is used by home gardeners around ornamental plants and vegetables for many reasons. Mulching, if done properly, can conserve soil moisture, prevent erosion, suppress weeds, moderate soil temperatures, prevent soil compaction from rain and foot traffic and increase the overall aesthetic appeal of plantings. An added benefit of mulching, one that many gardeners may not realize, is that it reduces the amount of rain-splashed soil on the foliage, thereby reducing the risk of certain diseases.
The many benefits of mulching are matched by the many types of materials that can be used as mulches. The ideal mulch material is affordable, readily available, easily installed and removed, stays in place, and is free of weeds, insects and diseases. Mulch can be made of organic or inorganic materials. Organic mulches include bark, wood chips, sawdust, straw, shredded leaves and cocoa bean hulls. Inorganic mulches include crushed stone and gravel. Organic and inorganic mulches have various advantages and disadvantages.
As the name implies, organic mulches add organic matter, and thus nutrients, to the soil as they break down. Some organic mulches, such as pine needles, peat and oak leaves, are acidic and can lower the pH, or acidify, of the soil. Acidic soil may be beneficial to plants that prefer a low pH, such as blueberries and rhododendrons. Organic mulches typically are applied between two and five inches deep, depending on the type of mulch material used.
Bark and wood chip mulches can be purchased at local department stores, home improvement centers and garden centers. Also, wood chip mulches often are readily available from local businesses that prune or trim trees. Sawdust is another organic mulch. Like pine needles, sawdust tends to lower soil pH, so it is best used around plants that prefer acidic soil conditions. Because it can become compacted over time, sawdust should not be applied in a layer more than two inches deep and should be fluffed up every growing season.
Straw is another readily available and fairly inexpensive organic mulch. It is effective and economical for use in vegetable gardens because it controls weeds and reduces water loss. But be careful to use clean, weed-free straw for mulching.
Leaves are probably the most readily available organic mulch for many home gardeners. If possible, leaves should be shredded and partially composted before use; otherwise, they tend to mat together and may prevent water and oxygen from reaching the soil.
Cocoa bean hulls are very decorative, so they typically are used as mulch in container plantings and highly visible flower beds. Because hulls are a processed mulch, they normally cost more than other organic mulches. Care should be taken in deciding where to use cocoa bean hulls for mulching because they can be blown away in strong winds or washed out by heavy rains.
Inorganic materials, such as crushed stone and gravel, are the other type of mulch used by home gardeners. These mulches do not blow away and can add a nice texture and color to flower beds and rock gardens. But be aware that limestone chips should not be used around acid-loving plants because the limestone will raise the pH of the soil, making the soil less acidic over time. Also, stone and gravel mulches are fairly difficult to remove if changes are planned for the planting area because the stones and gravel tend to become embedded into the soil. Inorganic mulches are very durable and persist for many years, but they do not decompose and add organic matter to the soil.
When deciding which type of organic or inorganic mulch to use, consider the area to be mulched, the type of plants growing in the area and the benefits, availability, cost and ease of use of the mulch material. Proper mulching can improve the appearance of your yard and garden as well as the overall health of the plants that surround your home.
-30-
Editors: There are no photos for this week's column.
ml: isugarden