This article appeared in the July/August 2001 issue of Horticulture Update, edited by Dr. Douglas F. Welsh, and produced by Extension Horticulture, Texas Agricultural Extension Service, The Texas A&M University System, College Station, Texas.

Much To Do With Mulch

By Wayne R. Pianta
Former County Extension Agent, Texas Agricultural Extension Service

Are you aware of the advantages of using a mulch in your garden? In one stroke you can reduce weed problems, improve soil structure, attract beneficial earthworms, keep the soil moist and cool, prevent erosion, and add nutrients to the soil. In short, good gardeners have much to do with mulch.

Texans should be thoroughly familiar with mulch; after all, nature has been depositing it for years on the floor of our Texas forests. Mulch is a ground covering, and the springy carpet of the forest floor is a natural example. The forest carpet decomposes, adding nutrients to the soil beneath. An organic garden mulch does the same thing for the garden, adding humus to the soil and improving its structure. Man simply takes his cue from nature, applying his own ground covering, natural or inorganic.

By depriving developing weed seedlings of light, mulch minimizes weed problems in the garden. The occasional weed that does appear is easier to pull. This easy weeding is the result of another benefit: moisture retention. Mulch slows moisture evaporation, protecting tender new roots from overheated soil while also lessening the watering chore.

A mulch can consist of inorganic or organic materials. Organic mulches include straw, pine needles, and bark. Inorganic mulches include gravel, stones, and even plastic. Availability is one factor to consider in selecting a mulch. Your choice of mulch depends on your personal preferences as to what looks the best and will be readily available. Of the materials listed, sawdust is probably the least desirable (even though it is available in most parts of Texas) because of its ability to rob nitrogen from the garden plantings. The key to using sawdust successfully as a mulch is to find well rotted and aged material. If you are tired of seeing the weeds in your garden doing better than the plants, or if you want to reduce your water chores and your water bill, give mulch a try in your garden.

Below is a list of mulching materials, along with their advantages or disadvantages (if any).

• Ground Bark
  Inexpensive, attractive, long lasting. Available in chip size or finely ground.

• Peat Moss
  Expensive and somewhat difficult to prepare. Initially attractive, but it can dry out, lose aesthetic appeal, and shed water.

• Pine Needles
  Durable, resist wind disturbance, locally abundant. Potential fire hazard when dry.

• Grass Clippings
  Available to most gardeners. Mat quickly, generating heat; disagreeable results if initial application is too thick. Spread thinly, allow to dry before applying to the garden. Do not use fresh clippings in your garden.

• Straw
  One of the best choices. Long lasting, can reduce moisture evaporation by as much as 70 percent. Will deplete soil nitrogen, which should be replaced by adding nitrogen fertilizer or blood meal.

• Sawdust
  Easily obtainable in many areas. Easy to handle, but can severely deplete nitrogen if not well rotted and aged. Supplemental nitrogen fertilizing may be necessary.

• Plastic Film
  Black polyethylene film is an excellent mulch, but unattractive where aesthetics are a consideration (it can be covered with decorative bark). Keeps soil temperatures even, eliminates weeds entirely. Punch holes in it for water penetration.

• Newspaper
  Readily available, builds humus. Can be used shredded or in sheets to desired thickness. Can be held in place by rocks, bricks, soil, etc., and covered for better appearance. The ink actually contains trace minerals beneficial to plant growth.

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