Thursday, September 20, 2007
For half a century or more, we have used synthetic chemicals to feed and medicate that universal icon of the American home, the lawn.
But in nurturing our own environments, many believe we damaged the broader world by relying on fertilizers and pesticides.
America's lawns receive 90 million pounds of herbicide each year, according to the environmental group Beyond Pesticides.
Paul Tukey, who ran a lawn-care business in the early 1990s, said he developed nosebleeds and shortness of breath after a spring of applying fertilizer and herbicides to his customers' lawns in Maine. This guided him to a path of organic gardening, and he has become, as an author and host of a gardening show on cable TV, a high-profile advocate for organic lawn care.
In this season of lawn repair, Tukey wants people to throw away the chemicals and switch to organic methods of establishing and maintaining turf grass. Not that he's alone.
Three years ago, the National Gardening Association polled consumers on their use of chemicals in gardening and found that although only 5 percent said they used strictly organic fertilizers and pesticides, 13 percent said they probably would go organic, according to Bruce Butterfield, the association's research director. About 35 percent used both organic and nonorganic products, he said. He plans to revisit the topic next year and expects to see at least a doubling of organic-only gardeners.
Meanwhile, organic products have become mainstream, with widespread retail distribution of such things as liquid seaweed and fish emulsion, and granular feeds made from livestock manure, poultry feathers and alfalfa meal. Even Scotts Miracle-Gro, which grew into a huge corporation selling bags of chemical fertilizers and herbicides, has moved into the organic arena. Among its many organic products is a new lawn feed, Scotts Organic Choice Lawn Food, made from feather meal and other animal byproducts.
Tukey, in his book "The Organic Lawn Care Manual" (Storey, $19.95), says that traditionally maintained lawns are chemically dependent, that it takes three years to transition to a sustaining organic turf and that the first step is changing the way we think about grass.
The organic farmer's mantra of feeding the soil, not the plant, applies to turf as well. Tukey and other critics of chemical lawn care contend that synthetic fertilizers, fungicides and insecticides damage soil structure and suppress the teeming microbial life in the soil. As a result, the thatch level at the crown of each grass clump builds up to such a level that moisture and nutrients are blocked and root development is diminished. The thatch layer becomes a breeding ground for insect pests.
He recommends rebuilding the soil life by top-dressing the lawn with screened compost and giving four yearly applications of compost tea, an organic brew made by placing organic solids and sugars in a mesh bag, immersing the bag in a large covered bucket and aerating it for a day.
Many of the steps in the manual are sound practices that are recommended whether or not you go organic:
* Get a soil test so you know how much feeding and liming is needed.
* Dethatch and aerate the lawn (see sidebar).
* Top-dress with compost and over-seed with the best grass varieties (in our area, generally, turf-type tall fescues developed for the hot, humid climate).
* Observe correct mowing heights (no shorter than 2 1/2 inches) and watering regimens (in summer, that means weekly soakings, not daily sprinkling).
It is in the feeding, weeding and pest killing that the differences introduced by an organic approach are most pronounced.
Lawns need feeding to remain thick enough to suppress weeds (and look good). For most of us, that means spreading a granular chemical fertilizer in the spring and fall. Whatever damage these fertilizers do, cumulatively, to the health of the soil, they are made in a process that involves burning large amounts of natural gas.
Natural alternatives include plant-derived nutrients such as alfalfa meal and seaweed, animal byproducts such as feather meal and fish emulsion, minerals such as greensand and rock phosphate, and livestock manures.
In these organic nutrients, the levels of nitrogen, potassium and phosphorus are generally lower than in synthetic feeds. Organic fans argue that the natural products release their nutrients over a longer period and that plants growing in microbially rich soil need fewer nutrients. The natural fertilizers cost as much as 50 percent more than the synthetics.
In organic treatment, weeds are either hand dug, mowed to prevent annual seeding, or spot-sprayed with organic herbicides. Citrus- and vinegar-based products are available. Household vinegar is not concentrated enough to work well, and some horticulturists also question the effectiveness of the more potent herbicide formulations.
Natural lawn-care companies use corn gluten to inhibit crabgrass seed germination in the spring, but Tukey acknowledges that it is only 65 percent as effective as synthetic pre-emergent herbicides. (A study by the University of Maryland found that corn gluten provided fair crabgrass control where weed pressure was low or moderate but was ineffective in heavily infested lawns.) Corn gluten, however, also acts as a nitrogen fertilizer.
For spot weeding, gardeners can get a propane-fueled flamer that vaporizes the offending plant. Tukey recommends one with an ignition switch because "I've scorched the hairs on my hand more than once by lighting a flamer with matches."
Burrowing white grubs of various beetle species, especially the Japanese beetle, can destroy turf by eating grass roots. One common systemic pesticide, imidacloprid, is highly toxic to honeybees. Organic controls include beneficial nematodes, tiny eel worms that eat the grubs, or milky spore, which is a bacterium that attacks the grubs. Tukey says other turf-destroying insects can be managed with nematodes and insecticidal soap and by dethatching.
Rich Martinez, chief environmental officer with Scotts Miracle-Gro, said the company makes organic lawn-care products and its lawn-care division provides organic services because consumers want the choice. As for the environmental benefits of organics, "we believe most of that is perception," he said.
David Clement, a home landscape expert with the University of Maryland, is skeptical of the claims of organic turf-grass advocates.
"Organic lawn care is fine, and you can do that, but when you have problems, very few of the organic solutions are as effective," he said. Following basic lawn-care practices such as mowing at the right height and over-seeding with superior varieties of grass seed will make most of the chemical tools unnecessary, he said.
"It's like any good gardening: If you do the right cultural things at the right time, you don't have a lot of problems," Clement said.
"I'm not sold that organic would be that much better than the regular regime," he said. "I know there are a lot of people who feel otherwise. It almost comes down to your belief values."
Todd Harrington, who runs an organic lawn-care company in Windsor, Conn., is among those who feel otherwise. "With chemicals, you're not really doing anything beneficial; you're polluting and you're taking risks," he said. "With organics, you're creating a sustainable environment."