UGA publishes turf care calendars for the various types of turf-grasses that are most commonly grown here in Georgia. Using the charts to plan lawn-care activities can save homeowners money and can also protect the environment.
For example, if seed or sod for a particular type of grass is planted (following appropriate guidelines - see UGA publication Lawns in Georgia) at the most-optimum time of year for that grass, the odds of a new lawn's survival improve dramatically over seed or sod set out at a less-than-optimum time. The improved survival rates mean the homeowner doesn't have to re-seed or set out new sod anytime soon, saving both money and time.
Following the UGA guidelines for when-to-apply-fertilizers improves the odds of the lawn's actually using the fertilizer, rather than having it wash away into storm-water drains, then into streams that flow eventually into the sources of our drinking water, burdening the treatment plants that then need to remove the polluting chemicals from the water before sending it back to homeowners. Along the way, the excess fertilizers can harm the fish and other animals that inhabit Georgia's streams and ponds. If applied at the right time in the right amounts, fertilizers nourish the lawn and are not wasted.
In general, warm-season grasses like Centipede grass, Zoysia grass, Bermuda grass, and St. Augustine grass should be fertilized in summer when the grasses are actively growing. The calendars for Centipede grass, Zoysia grass, Bermuda grass, and St. Augustine grass (click on the linked turf type for the care-calendar in pdf form) show the best months for applying fertilizers and pre- and post-emergent herbicides, for adjusting the soil pH, for aerating the soil, and more, for each type of grass.
For Fescue, the most commonly planted cool season grass, the general rule about applying fertilizer when the grass is actively growing is the same as for the warm season grasses, but the timing will be very different because its active growth season isn't in the summer months.The Tall Fescue care calendar (click on the linked name for the care calendar in pdf form) shows that the best months for applying fertilizer are February, March, October, and November.
When it doubt about the best time for a lawn-care task, the UGA lawn-care calendars can provide some helpful guidelines.