Average July rainfall for Dalton is almost 5 inches. This year, only two-thirds of an inch of rain was recorded.
Summer precipitation is nearly always associated with thunderstorms. Humid air at the land surface is heated and as that air rises, it also cools, condensing moisture and producing rain. Summer storms are often described as isolated, intermittent or scattered. This pattern results in substantial storms and rainfall in small areas, often adjacent areas that are unusually dry.
High temperatures, including warm nights, and adequate moisture provide ideal conditions for maximum growth by warm-season turf grasses. However, moisture, humidity and heat may also provide optimum growth conditions for lawn pests.
Clint Waltz, Extension turfgrass specialist with the University of Georgia's College of Agricultural and Environmental Sciences, suggests that staying on a schedule is appropriate for managing turf during the heat of summer.
“Just stay on schedule," he said. "We’ve been on a fairly good weather pattern this year, so stay on track taking care of your warm- and cool-season grasses by maintaining mowing heights, fertility programs and irrigation schedules.”
In addition to water, sunlight and nutrients, plants need oxygen. Waltz' recommendation to ensure adequate oxygen is to core-aerate lawns at least every three to four years, but more often in heavily compacted areas. August is still a good time to aerate warm-season lawns, including bermudagrass, centipede and zoysia. Best times to aerate tall fescue lawns is during October or March and April.
“Ultimately, the more oxygen you get to the root system the better,” said Waltz.
Lawns need about an inch of water per week, but shouldn’t be watered too often.
“Although we’ve had a good bit of rain in some parts of the state this summer, it’s typical to start seeing very hot, dry conditions late in summer and early fall, and we’re already seeing those conditions in some areas. The irrigation mantra is to water lawns deeply and infrequently,” said Waltz.
He tells residents to space out their irrigation schedules to about twice a week, making sure to get good saturation at each watering to encourage deeper root growth.
“As far as disease issues go, dollar spot in bermudagrass and zoysiagrass has been number one in home lawns in the last few weeks,” Waltz said.
He attributed the spike in cases to weather patterns typical of Georgia summers — late evening showers and high nighttime relative humidity. Dollar spot disease makes circular discolorations only a few inches in diameter. Spots may run together causing large, irregular patterns. Blades of grass have straw-colored lesions along one edge that spread across the leaf blade until the tips die back.
“Most commonly, when we see dollar spot appearing after prolonged rainfall events, we recommend homeowners look for strobilurin fungicide products — under the brand names Heritage, Disarm, Compass and Insignia — or DMI (demethylation inhibitor) fungicides — under the brand names Eagle, Banner, etc. There are many to choose from and all of them work well. However, dollar spot can sometimes be associated with a lack of nitrogen, in which case homeowners can add about .5 to .75 pound of nitrogen per 1,000 square feet on warm-season grasses,” said Waltz.
Tall fescue lawns struggle during peak summer conditions.
“It’s hanging in there, but in late July and early August the hot, dry conditions will trigger a defense mechanism in tall fescue,” explained Waltz. “The canopy begins to open up to conserve resources until late September and then will use those stored resources to regenerate. This happens every year, so don’t be alarmed. It will get bad, then worse, and then will start to turn around again in the fall.”
For tall fescue, maintenance differs from warm-season grasses. Waltz recommends deep and infrequent irrigation, no summer fertilizer applications and the use of fungicides as a preventative measure against brown patch. Georgia’s summer climate is ideal for brown patch fungal disease — areas of dead grass surrounded by a reddish-brown or purplish halo — to thrive. Ranging from a few inches to several feet in diameter, this disease occurs during periods of high humidity and warm temperatures (75-85 degrees). After two to three weeks, the center area of brown grass may recover and turn green, resulting in a doughnut shape of dead brown grass.
“Try to find a fungicide with a 28-day residual to help maintain the canopy, especially when there is limited air movement through late summer and early fall. Ideally, homeowners should rotate chemical classes to prevent resistance issues,” Waltz said of measures to prevent brown patch disease.
Roger Gates is the agricultural and natural resources agent for University of Georgia Extension, Whitfield County. Contact him at email@example.com.