Greening Your Lawn
Grass lawns have their benefits: the soil provides a home for worms and insects, which then provide delicious meals to birds; they can prevent soil erosion, filter contaminants, and absorb airborne pollutants; they clean the air as they convert carbon dioxide to oxygen. But, before you get out the hose to start watering your lawn for the warmer months, consider the fact that many households use more water outside in the summer than they do for everything else during the rest of the year. Though this includes washing your car, filling pools, and other outdoor activities, maintaining lawns and gardens accounts for the majority of increased summer water use. Typical suburban lawns consume thousands of gallons of water, in addition to the rainwater that falls on them. Taking good care of your lawn can save you time and money, prevent dangerous chemicals from entering the water, soil and air, and reduce yard waste.
To care for your lawn in an environmentally friendly way, the EPA recommends taking the following steps: developing healthy soil; choosing a grass type that fits your climate; mowing high, often, and with sharp blades (perhaps even using a push mower rather than the pollution-producing gas models); watering deeply, but not too frequently; correcting thatch (dead plant material) buildup; utilizing a holistic approach to pest management; and practicing natural lawn care. To learn more about these "greenscaping" tips, see http://www.epa.gov/GreenScapes.
Grass lawns prefer soil that is a good mix of silt, clay, and sand. If your soil is too sandy or has too much clay, consider adding compost, manure, or grass clippings, which will help in either case. Letting your grass grow long allows it to absorb more sunlight, which makes it grow thicker and develop a deeper root system. This will help your grass survive through droughts, insect problems, and diseases. This training of the roots to extend downward is also why watering deeply is beneficial. Meanwhile, the longer grass shades the soil, keeping it cooler and making it less likely that weeds will sprout. The EPA suggests a height of between 2.5" and 3.5" (though this depends on the species) and recommends mowing such that you never cut off more than one third of the grass height when you mow. In this way, you will be able to leave short clippings on the lawn to recycle nitrogen, rather than sending them to the landfill as waste.
When watering the lawn, aim for early morning, so that more of the water will be absorbed by the soil rather than evaporating. Only water when it is really needed - the grass will have a duller color, will begin to wilt, and will not rebound quickly after being stepped on. Consider getting a timer for your sprinkler so it does not run unnecessarily and make sure that it is aimed to cover the lawn only (not the sidewalk!). You can even purchase (or make) a rain barrel to catch precipitation and use it for watering the lawn rather than paying for water from the hose.
Though mowing the lawn is a necessary evil (unless you go all out and convert to more natural plant cover rather than grass), it is important to realize that gas-powered lawnmowers are not the best option. The EPA has estimated that the pollution from using one for an hour is equivalent to driving a car 20 miles. When added up, pollution from gas mowers is responsibly for 5% of the total US air pollution. Electric mowers, however, will significantly reduce this impact, and push mowers only require your own energy.
If you have a pest problem, consider natural remedies first. Pesticides used on lawns pose a threat to wildlife, soil, and water. Many chemicals found in them can cause birth defects or are thought to be carcinogenic. There are a great many suggestions available for dealing with various problems, including setting out trays of beer to attract and kill slugs and spraying your plants with various simple concoctions that will make them less appealing to insects. Remember that the majority of bugs in your garden are beneficial!