One of the best green thumb practices for Galveston County gardeners is the use of mulch.  Mulching is a long-established horticultural practice that can save time and money.  Use of a mulch can also provide significant benefits to landscape plants by reducing damage to trunks caused by lawn mowers and line trimmers.

What is a mulch?  By definition, it is a protective ground cover that reduces evaporation of soil moisture, helps maintain uniform soil temperatures, reduces soil erosion, controls weeds, and, in the case of organic mulches, enriches the soil.

Mulches can be classified as organic or inorganic.  The organic mulches are the most popular and widely used by gardeners.  These include a variety of materials, such as straw, compost, leaves, pine needles and barks.  Inorganic mulches include plastic, rocks, chips and other non-plant materials.

One of the major advantages of mulch is the reduction in soil moisture loss by up to 70 percent.  This is especially true with a reasonably thick layer of organic mulches.  Given residential water costs, this should be a primary reason for encouraging the use of mulches.

The insulating value of mulches helps keep the soil cooler in the summer and warmer in the winter.  Better growth of your plants throughout the growing season will occur if excessive fluctuations in soil temperature can be reduced.

Erosion control is also an important function of mulch.  While we have a fairly flat topography, erosion can be a concern especially in sloping areas or bare areas that are exposed to heavy rains.  Mulching helps reduce rain splash and runoff, which in some cases can significantly reduce the spread of several types of plant disease organisms.

Another major benefit of mulching is the suppression of weeds.  A 4-to-6 inch layer of organic mulch should be sufficient to prevent sunlight from reaching the soil, thereby reducing the incidence of weeds.

Mulch will not prevent all weed seeds from sprouting.  However, a thick layer of mulch keeps most annual weed seedlings from coming through.  Weeds that do manage to break through are easily pulled including nutgrass.

Another benefit of organic mulches is that they enrich the soil as they decay, forming a rich, dark, organic material called humus.  Humus provides nutrients to the soil thereby enhancing soil fertility.  It also improves the soil structure of our gumbo clays (i.e. it loosens up tight clay particles).

Last but not least, mulch has aesthetic value.  The range of colors and textures available offers a material for almost any landscape or garden.  The uniform quality added to the "garden floor" serves much the same aesthetic purpose as carpet does inside the home or the lawn outside the home.

So what are some of these marvelous mulches?  There are many available.  Keep in mind that using a material that is readily available will cost less and most likely will be better suited to your landscape.

Bark chips.  This type of mulch is long-lasting and attractive.  Because bark chips break down slowly, this type mulch may not be as much value as some others in improving the soil.  Bark is relatively easy to apply, but it has a tendency to float away in heavy rains.  Pine is the most commonly used.  Although not as abundant, cypress is becoming very popular and breaks down more slowly than pine bark.

Shredded bark.  This is probably the most popular mulch used with pine being the most common type.  It's very attractive and easy to apply.  Shredded bark has excellent insulating properties to help maintain uniform soil temperatures.

Compost.  This makes an excellent mulch.  However, due to the mix of material used to make garden compost, the lack of uniformity may render it less attractive.  Unless the compost pile heats up to 140 to 150 degrees, finished compost is also the most likely mulch to contain weed seeds.

Leaves.  Leaves are one to the least expensive mulches available to a gardener.  However, they are difficult to apply evenly, are mostly seasonal in availability, and sometimes takes months to decompose.

Pine needles.  Abundant in some areas, this popular mulch provides a uniform covering for beds and pathways.  Because pine needles are moderately acid, they are well-suited for acid-loving plants such as azaleas and gardenias.

Inorganic mulches.  River stones, pebbles and gravel chips are all good mulches.  Though they do nothing to improve the soil structure or fertility, these materials can be aesthetically striking.  They will not require replenishing as frequently as the organic materials.

Landscape fabrics.  These new materials can be used in conjunction with other mulches.  Typically, fabric is laid and one of the previously mentioned mulches is placed on top.

Because organic mulches decompose and can "burn up" due to the intense summer heat in the Galveston County area, they will need to be added to or replaced periodically.



This web site is maintained by Master Gardener Laura Bellmore, under the direction of William M. Johnson, Ph.D., County Extension Agent-Horticulture & Master Gardener Program Coordinator.

All digital photographs are the property of  the Galveston County Master Gardener Association, Inc. (GCMGA) 2002-2006 GCMGA - All Rights Reserved.