By Stephanie Schupska
University of Georgia
For research-based information, they can turn to University of Georgia turfgrass experts for solutions to their problems -- from the best grass for a lawn makeover to ground cover under an oak tree.
When a client called a UGA Cooperative Extension office recently about problems with thinning grass in an increasingly shady lawn, state turfgrass specialist Clint Waltz had to think about his answer for a moment. Georgia covers three plant hardiness zones, making it impossible to pick one grass that would work for the whole state.
"The best grass for their lawn would depend on where they live in Georgia," he said. "If you live south of Macon, St. Augustinegrass would be the best. Our most shade tolerant warm-season turfgrass is St. Augustinegrass. If you live near Atlanta, tall fescue would be an option, and possibly St. Augustinegrass, depending on the cultivar."
"Sometimes as landscapes grow up, you may want to think about removing tree limbs to let sun in," said Extension specialist Tim Murphy.
Before planting any new grass, though, the best starting point would be to submit a soil sample to a local Extension agent for testing. This allows the homeowner to properly fertilize and lime the lawn, without the usual guesswork.
"If your yard has bare spots because of nutrient imbalance or shade, you're going to need to do something besides seed or add new sod or grass plugs," Waltz said. "If the problem is soil compaction, you need to aerate the ground to make it conducive for growth."
Before laying grass seed or sod, Murphy said to prepare the bare soil by lightly tilling it. Then prepare a smooth seed-bed and seed or sod it.
Sometimes a homeowner may consider overseeding a sparse lawn. This tactic can be beneficial or harmful, depending on the type of underlying grass.
"If it's a warm-season grass like centipedegrass, zoysiagrass or St. Augustinegrass, or even bermudagrass, my suggestion would be not to overseed," Waltz said. "If it is summer and tall fescue, which is a cool-season grass, that's to be expected. If it's sparse in spring and fall, then you can overseed."
The best time to seed and establish cool-season grasses like tall fescue is between Sept. 15 and Oct. 15. It can be established in the spring, but summer's heat can put extra stress on tall fescue, making it hard for the grass to survive.
Survival will not happen, though, if the grass does not get enough light.
"Not all situations are conducive for grass," Waltz said. "Under an oak tree, for example, you may want to consider mulch or another shade tolerant vegetative cover. Grass will not grow under an oak tree because of the low light environment. That winds up being the prevailing reason. All grasses need some kind of light."
He suggests using a shade-tolerant ground cover instead of trying to get grass to grow right up to the tree's base.
(Stephanie Schupska is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)