MSC Press Releases 2005

Fall is for Mulching
by Cathy Wilkinson Barash

The single most timesaving practice for any gardener is using mulch around garden plants. Mulching goes hand in hand with planting-in fall or any other time of the year. You can buy various types of mulch or use leaves (chopped, shredded, or composted) or other garden material you already have.

Mulch performs several functions. A layer of mulch at least 3 inches thick produces a barrier to weeds; most weed seeds in the ground do not have enough light and air to grow through the mulch. In addition, the ground is protected from weed seeds dropped by birds or animals.

An organic mulch, such as bark nuggets, shredded bark or wood, chopped leaves, pine needles, leaf mold (composted leaves), or cocoa hulls, conserves water. Water the plant and surrounding soil well, add the mulch, and then water again. Take care to keep the mulch an inch from the plant stem or you risk suffocating it. The mulch prevents moisture evaporation from the ground, especially in the heat of summer. Using organic mulch has an added bonus; as the mulch decomposes, nutrients enrich the soil.

Mulch Insulates the Soil for Winter

Mulching is even more important at this time of year as the weather changes and the temperatures drop. A three- to six-inch layer of organic mulch helps maintain soil temperature. In areas where the ground freezes, this is particularly important as the layer of mulch prevents the ground from warming during “January thaw” and heaving plants out of the ground. Lack of winter mulch leads to the death of many perennials and small shrubs as the roots are pushed out of the ground during a thaw; when the temperatures drop back below freezing, the tender roots cannot tolerate the exposure to the air, and the plant dies.

In cold-winter regions, wait to add winter mulch until the ground has frozen. If you mulch too early in fall, the mulch will keep the soil at above-freezing temperatures and encourage the plant to keep growing. Unfortunately, the tender new growth is susceptible to the cold air temperature and is likely to be killed. Normally, as the temperatures fall, plants go into dormancy, which prevents most dieback.

Even though they are not visible in fall, most spring-blooming bulbs benefit from a good winter mulch, as do hardy perennials that have died back to the ground. Hybrid tea and grandiflora roses need a good mulching to make it through sub-freezing winters. Make a note to begin removing the mulch in late winter to early spring as days start to warm; you don't want to miss any of the spectacular early show of color that begins with small bulbs and woodland perennials and continues through spring and into summer.

SIDEBAR: CAVEAT EMPTOR - BUYER BEWARE

Unfortunately, all mulches are not created equal. Some mulch purveyors use recycled wood in their product; that's no problem unless the product includes preserved wood that contains CCA (chromated copper arsenate, an arsenic-based pesticide that's registered and controlled by the Environmental Protection Agency [EPA]). When buying mulch, look for the Mulch & Soil Council (MSC) Certification logo. Certification guarantees that every product and performance claim on the label, including volume contents, is randomly inspected, verified, and documented. The logo is an assurance that the mulch in the bag:

• Matches the product label
• Properly identifies product content for user comparison
• Meets accepted industry standards, including random testing
• Does not contain CCA-treated wood.

For example, when you buy a bag of pine bark mulch with the MSC certification logo, you know for sure that what's in the bag is only pine bark with no other material mixed in; if it is a mixture, it must be labeled as such, with each ingredient listed clearly in declining order by volume. Certified mulch is safe to use in your garden-free of CCA contaminants. Without the MSC certification logo, you cannot be sure what you're getting.

The Home Depot is the first retailer to require mulch suppliers to certify their products. The Company currently is rolling out a program to offer certified mulch in all The Home Depot stores. MSC certified mulch is also available at major nurseries and garden centers. For more information on MSC mulch certification and a list of certified products, visit the MSC Website at www.mulchandsoilcouncil.org.

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Cathy Wilkinson Barash, an award-winning writer and photographer and author of 13 books, is immediate past president of the Garden Writers Association. She currently gardens-and is busily mulching-in Des Moines, Iowa.