Don't get talked into paying for treatments your yard doesn't need. By Sean O'Neill March 31, 2006 1. You may not need all those chemicals. Lawn-care providers rake in a lot of green for treating your lawn to get rid of weeds and pests. The typical homeowner spends $200 a year on such services. But as a rule, proper irrigation and mowing will fortify your lawn against pests and disease as well as chemicals can. To find out whether your lawn is suitably moist, probe it with a screwdriver. The soil should be moist to a depth of up to 4 inches. A hint: Occasional soakings strengthen roots better than frequent mistings.2. Their "preventive" treatments may be overkill. Customers may be persuaded to pay for additional treatments to prevent diseases and deter garden pests at a cost of $50 to $100 a year. But the risk of disease may be far lower than the lawn-care company claims, according to Phil Busey, a professor of environmental horticulture at the University of Florida. For an impartial assessment of the risk of disease in your area, contact the county or regional arm of the U.S. Department of Agriculture. The federal agency lists its extension offices at www.csrees.usda.gov/Extension. 3. That aeration service they're plugging could be a gimmick. Many companies tout aeration -- or plugging your lawn with small holes -- as a way to thwart fungal growth, dry patches and other evils. That's because the pros charge between $8 and $15 per 1,000 square feet to aerate your lawn. (A typical 5,000-square-foot lawn costs between $40 and $75 to aerate.) But, says Trey Rogers, a professor of crop and soil sciences at Michigan State University, recommending aeration for a healthy lawn is "like telling a guy with a full head of hair that he'd better take some anti-baldness medicine." 4. They may not have a license to kill. Search for a certified professional at the Professional Landcare Network's Web site. Once you pick a pro, ask to see a current pesticide license (sometimes called a state certification). Bill Phagan, president of Green Industry Consulting, estimates that just one in ten lawn-care workers who apply pesticide treatments in Florida have licenses to do so. Advertisement 5. Got weeds? Blame the service that mows your lawn. A thick lawn denies weeds the space they need to grow, so the best mowing services will also thicken your lawn. How can you tell the job has been done right? When the sidewalk edges are trimmed to the same height as the rest of the lawn, not scalped. Improper edging and mowing stress grass, and stressed grass won't thicken and develop a deep root system to resist weeds, says Rogers. 6. The grass may be greener. Most lawn-care contracts are oral, not written, and you can cancel at will. The best time to comparison-shop is between January and April, when companies compete aggressively on price.