Townsman article

Submitted by Sarah Little, Wellesley Pesticide Awareness Coordinator

On behalf of the Wellesley Pesticide Awareness Campaign

s-little@mediaone.net

Monday, April 30, 2001

Last month, a Wellesley Pesticide Awareness Campaign flyer from the Board of Health went out with the utility bill to every resident in town. We are hoping people will take its message to heart. The Campaign is working hard to educate people about the hazards of pesticides, the benefits and beauty of organic lawns, and the methods to transition to healthier lawn care. Since the flyer went out, we have received quite a few calls with questions about how to maintain lawns without using pesticides. In an effort to encourage people to adopt pesticide-free practices, we will regularly publish answers to some of the most frequently asked questions here in Wellesley. We have enlisted the help of several organic land care professionals, Priscilla Williams and Mike Nadeau of our partner organization, the Northeast Organic Farming Association, and Peter Wild of Boston Tree Preservation, to get the most up-to-date information on organic materials and techniques.

This week we will address the problem of crabgrass. Many people assume that they must apply a pre-emergent herbicide to prevent this and other weeds. Pre-emergent herbicides are poisons with varying degrees of acute toxicity depending on the specific formulation. Some of the chemicals used are possible carcinogens and suspected endocrine disruptors. None of these chemicals have been tested for their effects on children. You don’t need to use these because there are some simple, non-toxic, readily available alternatives.

The first step in dealing with weeds is to realize that many so-called “weeds” are actually beneficial to the lawn ecosystem. It wasn’t until the advent of selective herbicides that a lawn consisted of only grasses. Before that, any plant that lived under the mower blade was considered “lawn,” and these lawns were often more tolerant of adverse conditions than chemically dependent lawns.

However, excess weeds are often a symptom of poor soil, a flag that lets you know a pH adjustment is needed. Correcting the soil pH ultimately crowds out the weeds, as healthy turf and weeds cannot co-exist. The turf will shade out the weed. The ideal lawn pH is between 6.8 and 7.0.

In some cases, weeds can get out of hand and take over sections of lawn. If weeds need to be controlled, there are several less toxic organic products on the market approved for use. Corn gluten meal acts as a pre-emergent weed control that suppresses the establishment of plant weeds. It is applied in the spring between Forsythia and Lilac bloom, before weeds such as crabgrass emerge. It can be reapplied in early summer to prevent late-season weed seeds from germinating. Crabgrass can also be effectively managed by hand pulling before it goes to seed.

Because corn gluten meal is high in protein it contains approximately 10 percent organic nitrogen. This nitrogen level needs to be accounted for in the overall lawn management program, so that nitrogen is not over applied during the season through additional fertilizer and compost applications. The bare spots in the lawn where crabgrass was last year, treated with corn gluten, can be planted with an annual rye grass to “hold the spot” until a perennial lawn seed mixture can be established in the fall. Seed applied after corn gluten should be mixed with compost and the compost spread at least 2 inches thick in the bare areas.

Our next article will address the organic approach to controlling grubs in lawns. In the meantime, if you would like more information on organic lawn care, please visit our web site at www.ci.wellesley.ma.us/nrc/pesticide, or call the Natural Resources Commission at (781) 431-1019 x294.

Corn gluten is available at the Needham Garden Center, 53-R Chestnut Street, Needham, along with a selection of organic fertilizers, soil amendments and organic compost. Wellesley residents mentioning this article will receive 10% off their purchases.