Grow An Earth-friendly Lawn
Learn the organic way to maintain your yard and garden
By Kathleen Christensen
Photo: Chislain & Marie David De Lossy/Getty Images
The 3-year-old lays her stuffed lemur down on the lawn for a nap, then makes mouse houses out of grass clippings. Dad brings out a bowl of home-grown raspberries—organic, of course—while Mom, newly pregnant and a little tired, flops down on the grass and tosses a tennis ball for the family’s golden Lab. Is there a more sublime place to hang out than a sun-soaked lawn?
Now add this to the happy picture: Yesterday, Dad sprayed a little weed and feed—a mixture of weed killer and synthetic fertilizer—on the lawn. Of course, Mom didn’t let the family outside until it dried, as the manufacturer recommends. So everyone’s safe, right?
Maybe not. Researchers have linked the herbicides in weed and feed with everything from cancer to infertility to problem behavior in kids. In fact, it’s illegal in the United States to claim on product labels that pesticides, including herbicides are “safe.” But here’s the good news: With a little know-how, you can grow a lovely, green lawn that’s as organic as your favorite tomatoes.
Dangers of lawn pesticides
It may surprise you to know that U.S. homeowners use up to ten times more pesticides per acre on their lawns than farmers use on crops, according to the U.S. Fish and Wildlife Service. Does this intensive use of lawn chemicals present a health risk? “Unfortunately, we don’t have complete human studies,” says Leo Trasande, MD, MPP, an environmental pediatrician at the Mount Sinai School of Medicine in New York. “But we’ve seen some very concerning research.”
Cancer is one possible danger, for people and pets alike. Studies, including some by the National Cancer Institute (NCI), have linked five of the most popular ingredients in home and garden pesticides with non-Hodgkin’s lymphoma—the sixth most common cancer in the United States. NCI research also suggests an association between 2,4-D—the most common herbicide in weed-and-feed products—and lymphoma in dogs.
If you hope to have children, you may also be concerned about reproductive risks. Pesticides may contribute to lowered fertility in men; for example, researchers found an association between poor semen quality and levels of several pesticides in the urine of men from rural Missouri (Environmental Health Perspectives, 2003, vol. 111, no. 12). And in a Minnesota study, the birth-defect rate was elevated in children born to pesticide appliers compared with all children born in the state during the same time period (Environmental Health Perspectives, 1996, vol. 104, no. 4).
In particular, pesticides pose significant health risks to children, according to Trasande. He cites studies that raise concerns about childhood brain cancer and leukemia, impaired development of the reproductive system, and neurological and developmental problems. “People should carefully consider these potential risks before using pesticides,” he says.
Unfortunately, avoiding pesticide exposure is not as simple as closing the door. “If you use [pesticides] on your lawn, they get tracked into your house,” says Robert Gunier, MPH, a research scientist with the California Department of Health Services. In one study, researchers estimated that after 2,4-D lawn application, indoor exposure levels for young children were ten times greater than before the applications—and that exposure levels from contact with exposed floors and tabletops were up to 30 times greater than dietary exposure levels (Environmental Health Perspectives, 2001, vol. 109, no. 11).
Also troubling, according to Gunier, is that many lawn pesticides remain active in the soil for months after application; under certain conditions, some can even persist for years. Pesticides and herbicides can also drift with a breeze—for example, over the fence from your neighbor’s yard into yours. In fact, a U.S. Geological Survey review found 2,4-D contamination in more than 60 percent of air samples collected throughout the country (Journal of Pesticide Reform, 1999, vol. 19, no. 4). Still, not using pesticides and herbicides in your own yard will help lessen your exposure.
Organic a good choice, even for weeds
If you decide to eschew pesticides on your lawn, you’ll do well to avoid synthetic, or man-made, fertilizers, as well. Synthetic fertilizers do stimulate your lawn so it gets green rapidly, but they tend to leach quickly out of the root zone, leaving the grass hungry again. Most supply a few major nutrients but no micronutrients or organic matter. Synthetic fertilizers and pesticides also kill earthworms and beneficial soil microorganisms—both vital contributors to a healthy soil.
In contrast, an organic diet can be as healthy for your lawn as it can be for you. Compost improves the texture of the soil, enabling it to hold air and water properly and encouraging grass roots to grow deep. Organic fertilizers provide a steady supply of nutrients—not just nitrogen, phosphorus, and potassium, but a complete complement of both macro- and micronutrients. Earthworms and soil microbes aerate the soil and break down organic matter—including thatch and grass clippings—into plant food.
Now, you may still be wondering how you’re going to control weeds in your yard without any help from chemicals. Herbicides are, after all, among the most common pesticides used by homeowners on lawns. However, they don’t really solve your weed problem. “Herbicides make a cosmetic change to your lawn, but they don’t change the underlying conditions that promote weed growth,” says Tim Gilpin, PhD, an environmental chemist and the owner of Native Solutions Inc., an organic pest control and lawn-care company based in Boulder, Colorado.
What does weed out the weeds? Organic weed management in a lawn is mostly about competition. “A thick lawn crowds out the weeds,” says Gilpin. Everything you do to nurture thriving grass—from maintaining soil health to mowing and watering correctly—helps the grass outcompete the weeds.
You can hand-weed as well, of course, but there’s another, more realistic option available nowadays. In the 1980s, researchers at Iowa State University accidentally discovered that corn-gluten meal can help reduce weed populations in lawns. The product doesn’t kill established plants but helps prevent crabgrass, dandelions, and other broadleaf weeds from germinating successfully. “It’s considered 60 percent to 90 percent effective, and possibly 90 percent after the first year,” says Gilpin, “but it’s not a magic bullet.”
Resources
Beyond Pesticides:
www.beyondpesticides.org
Center for Children’s Health and the Environment, Mount Sinai School of Medicine:
www.childenvironment.org
“Healthy Lawn, Healthy Environment,”
a brochure provided by the United States Environmental Protection Agency (EPA):
www.epa.gov/oppfead1/Publications/lawncare.pdf
Northwest Coalition for Alternatives to Pesticides:
www.pesticide.org In the end, reexamining your attitudes toward weeds may be a good solution. “When I see a lawn from the street and it has 10 percent weeds, I can’t really tell they’re there if the grass is tall and lush and healthy,” says Gilpin, who points out that a scattering of broadleaf weeds such as dandelions actually can be beneficial for a lawn. Many have thick taproots that bring up nutrients from down deep; when the weeds die and break down, they release those nutrients into the top layer of soil, where grass roots can soak them up. Some weeds also provide habitat for beneficial insects.
For Gilpin, growing an organic lawn entails “enjoying nature and understanding it and working with it.” When you understand how to grow an organic lawn, he says, you understand a little more about all ecosystems. “It’s about maintaining balance and health,” he says, “for people and the environment.”
Writer Kathleen Christensen is looking forward to kicking a soccer ball around on organic turf the next time she and her family visit her 6- and 4-year-old stepgrandsons in Marblehead, Massachusetts.