Soil expert Debbie Joines of the University of Tennessee Agricultural Extension Service discusses the various kinds of mulches. Mulch is any material used to cover the surface of the soil. It may consist of pine needles, leaves, shredded newspaper or even gravel. Mulch helps keep the soil's temperature constant, reduces weed germination by preventing weed seeds from receiving sunlight, slows moisture loss and reduces erosion from heavy rainfall. Organic mulches such as straw or leaves will eventually break down and add nutrients to the soil. Bark mulch is attractive and relatively long-lasting but can be expensive. To save money, apply a mulch of homemade compost. If your compost pile is sufficiently hot, you won't need to worry about weed seeds surviving the composting process. Apply a 2" to 3" layer of compost to the soil surface in fall or spring. Straw makes a good mulch for vegetable gardens (figure A). It's available at feed stores and costs about $6 per bale, enough to cover a large garden. Apply straw 4" deep around vegetable crops. Straw helps reduce the soil temperature and also protects plants from soil-borne diseases that are spread when water falling on soil splashes onto foliage. If you use grass clippings as a mulch, apply a layer only 1" to 2" deep: grass generates a great deal of heat as it decomposes. If the lawn consists of Bermuda grass, you may have problems with unwanted grass seedlings germinating unless you compost the clippings first. Pine needles are used to cover strawberry beds in winter (figure B). As pine needles break down, they acidify the soil, making them a good mulch for acid-loving plants such as rhododendrons. Apply a layer of pine needles 2" to 3" deep. Leaves raked from your lawn can also be used as a mulch. As they break down into compost, they'll add organic matter to the soil. If you live along a coast, consider using seaweed as a mulch (figure C). Manmade fabrics perform many of the same functions as organic mulches, although, of course, they add nothing to the soil. Black plastic may be used as mulch in a vegetable garden. To water, lay a soaker hose on the soil before putting down the plastic. Landscape fabric permits water and air to pass through and may be placed directly on the surface of the soil. To plant, first cut an "X" in the fabric (figure D). If you don't like the look of the fabric, apply bark mulch on top of it.
GUESTS :
Debbie Joines
UT Agricultural Extension Service
5201 Marchant Drive
Nashville, TN 37211-5201
Phone: 615-832-6802
Fax: 615-832-0043
Email: djoines@cru.gw.utk.edu
Website: http://www.utextension.utk.edu
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