By Sharon Omahen
University of Georgia
Every spring, homeowners start paying more attention to their lawns. And when it comes to preventing turf diseases, University of Georgia experts say it's better not to go overboard in caring for your grass.
"Ninety percent of turf disease could be prevented if homeowners properly managed their lawns," said Mila Pearce, an integrated pest management specialist with the UGA College of Agricultural and Environmental Sciences.
Pearce spends her days identifying plant diseases from samples or digital images forwarded by county extension agents and homeowners to her Griffin, Ga., lab. She diagnoses ornamental, turf, orchard and vegetable problems on home and commercial landscapes and golf courses. "I can make chemical recommendations," she said. "But unless you correct what you're doing wrong to welcome diseases to your lawn, you're just spraying money onto your lawn."
The No. 1 mistake
Pearce says the No. 1 mistake homeowners make when caring for their lawn is overwatering. Drought-enforced watering schedules often result in home owners watering their lawns too much, too. "Water studies suggest that when they have to abide by a watering schedule, people apply water several times in short intervals to their lawns," Pearce said. "This creates turf diseases. And, ironically, it may increase water consumption."
One reason too much water can be harmful to your home lawn is that it creates a perfect environment for diseases.
"Diseases love warm temperatures and high humidity," she said. So how do you give your lawn the water it needs without putting out a welcome mat for unwanted diseases? Pearce recommends irrigating your lawn in the early morning.
"This gives your lawn plenty of time to dry during the day," she said. "You want to maximize the amount of water consistent with good growth but with the least amount of surface wetness." An example would be to water thoroughly once a week until the top 1 or 2 inches of soil is wet, as opposed to watering three times a week for 30 minutes. "The longer any plant is wet, Pearce said, "the more you invite diseases."
So how much water do you really need?
Base the amount of water you apply on the type of soil you have. "In south Georgia, the sandy soils allow for most turf grasses to be watered one day a week," she said. "But if you live in north Georgia, the clay soils tend to hold water longer, and this may allow homeowners to decrease irrigation intervals."
Just as their soils differ, the different grasses grown in north and south Georgia allow for disease disparities.
North diseases, South diseases
"Homeowners in south Georgia are beginning to see Take-all root rot in their lawns," Pearce said. "It mostly affects St. Augustine and Bermuda grass, and the symptoms are die-back, browning and thinning."
North Georgians typically see more brown patch. People often start out with a disease called dollar spot, Pearce said.
The control recommendation for dollar spot is a proper irrigation and fertilization schedule. "Homeowners usually overdo it and end up with brown patch, which is caused by wet soils and high fertility," she said. If you think you have a disease in your lawn, or you're not sure which fertilizer to apply, or how often to water your lawn, Pearce has a one-size-fits all recommendation. "When in doubt, call your county extension office," she said. "They'll know exactly what to recommend for your area and for your specific grass type."
And chances are, if they aren't sure which disease it is, they'll call Pearce for help.
(Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)