Aerating a lawn means poking thousands of small holes into the soil. These holes help the soil and grass roots absorb oxygen, water and fertilizer more readily. Aeration should be done as close to the start of the growing season as possible. Most fescue lawns should be aerated once a year, but high-traffic fescue lawns may benefit from twice-yearly aeration. Ideally, aerate in fall when this cool-season grass grows most vigorously. If you must aerate a fescue lawn in summer, do it as close to September as possible.
Resume a regular watering schedule 3 to 4 weeks before you plan to aerate. Most homeowners cut back on water and allow their fescue lawn to go dormant in the summer. To aerate the fescue in summer, resume your watering schedule to break its dormancy.
Water the lawn the day before you plan to aerate.
Push the core aerator over the lawn in rows, much as you would a lawn mower.
Go over the lawn with the core aerator again. This time, work at a 90-degree angle to your initial direction.
Examine 1 square foot of the fescue lawn. Ideally, it should contain 12 aerator hoes. If the number of holes is significantly below this, go over the lawn with the core aerator again, working diagonally across the lawn.
Fertilize the fescue lawn. Normally, you do not fertilize fescue in the summer. However, grass should be encouraged to grow right after aeration so that it can repair its broken roots. Spread a 16-4-8 fertilizer over the lawn at a rate of 6.25 pounds of fertilizer per 1,000 square feet. Since fescue is not normally fertilized in summer, remember to take this fertilization into account the next growing season so that you do not over-fertilize the lawn.
Water the fescue lawn once daily for two weeks until the grass recovers. Then continue a regular watering schedule throughout the rest of the summer. When fescue is fertilized in summer, it becomes more susceptible to drought. Keep a close eye on the moisture level of your soil. When the top 2 inches of the soil become dry, water the lawn.