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Evanston has started plotting how to reduce its carbon footprint, and its lawns are a large part of the picture.

A pleasant summer bike ride away in Lincoln Park is The Nature Museum’s current exhibit, Lawn Nation (www.naturemuseum.org). The exhibit makes clear that American lawns are responsible for a vast amount of energy use and CO2 emissions. The exhibit illustrates the environmental challenges of maintaining our lawns and our lifestyle, as we try to reduce our collective carbon footprint.

Also weighing in on the subject of lawns this summer is Elizabeth Kolbert (“Turf War”, The New Yorker, July 21). She notes that, “as the anti-lawnists correctly observe, the American lawn now represents a serious civic problem. That the space devoted to it continues to grow – and that more and more water and chemicals and fertilizer are devoted to its upkeep – doesn’t prove that we care so much as that we are careless.”

The amount of energy used and resultant carbon dioxide emissions in the creation and maintenance of lawns is enormous. There are three main areas in which lawns are environmentally demanding: water use; chemical, fertilizer and pesticide use; and maintenance.

Lawn Facts and Water Use

Lawns are the single largest irrigated crop in the U.S.

Landscaping accounts for a third to a half of all residential water demand.

Lawns use an average of 200 gallons of water per person per day.

Lawns use an average of 10,000 gallons of water per lawn each summer.

Solutions

A lawn can be allowed to become dormant in a dry summer. Trees need watering more than lawns. Lawns can grow back.

Turn off sprinkler systems during periods of adequate rainfall.

When watering, do it deeply, infrequently and in the morning.

Avoid sprinklers that shoot water in the air, as some of that water is lost to evaporation before it hits the ground.

Use rain barrels. That way, treated drinking water is not being used for irrigation. Water treatment uses energy.

Chemicals, Fertilizer and Pesticide Use

Chemicals on lawns get tracked into houses by people and their pets, so that what one person puts on his lawn may end up in someone else’s house.

The chemicals may contaminate storm water run-off and ground water. Julie Siegel, landscape designer, says excessive nitrogen applications result in a “lawn on life support.” Root systems are not able to develop adequately.

Solutions

The idea of a “Freedom Lawn” is that a common mix such as bluegrass, clover and whatever else happens to seed itself is simply mowed. This approach amounts to letting the plants fend for themselves. The diversity of the plant materials in the lawn keeps it healthy, with no chemical assistance and less water. Stephanie Levine, City of Evanston landscape architect, says Evanston’s parks reflect this approach. Only the James Park and Lovelace Park athletic fields and the Rose Garden, are irrigated.

Before any fertilizer is added, soil testing can determine which nutrients are missing. Natural fertilizers, including household compost, are beneficial, as are the grass clippings that remain after mowing. Vinegar or boiling water can be used on weeds, and garlic concentrate helps with grubs. Kathy Lorden of Lorden’s Landscaping says customers of lawn service companies are increasingly asking for lawn treatments that are not harmful to children and pets.

The Nature Museum features a low-maintenance and sweet-smelling clover and thyme lawn.

Maintenance

The environmental problems associated with lawn mowers, leaf blowers, and edgers relate to the excessive CO2 emissions, air pollution and noise associated with them. They also create health problems for people using them and exposed to them.

Since many communities have adopted partial or complete bans on leaf blowers (Evanston has had a seasonal ban since 1996), the companies appear to be making quieter equipment. But, to paraphrase one Evanston alderman, she will support Evanston’s ordinance “until a leaf blower is as quiet as a rake.”

The trusty push mower has enjoyed a resurgence for certain lawn sizes.

Breaking the Lawn Habit

The idea of getting rid of grass is psychologically difficult for most people.

But having a nice lawn should not be an either-or question. As with many sustainability and lifestyle decisions, there is a menu of options. One choice is to reduce the amount of lawn and replace some of it with buffalo grass, miniature thyme, low-growing sedge, wildflowers, grasses or vegetable gardens. Children can learn more from watching the cycles of plants and vegetables growing than from a homogeneous lawn. Native plants have a better chance of thriving in the prairie soil that is common here. They thrive without human attention, pesticides, chemical fertilizers or mowing and with what rainwater they get. The idea is to work with the natural tendencies of grass rather than to fight them.

A major goal of the lawn industry is to develop new grasses through genetic modification that require less water, fewer chemicals and less mowing.