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Gardening in Gwinnett: Fall is the best time to renovate fescue lawns

Tall fescue is a popular grass in our area, and is easily established through seed or sod. This grass holds its green color during the winter months while warm season grasses, like Bermuda and zoysia, go dormant and turn brown.

Being a cool season grass, tall fescue grows best during the cooler months of the year. During the hot summer months it requires the addition of supplemental water to stay green and healthy.

The best time of the year to plant tall fescue in our area is from the middle of September to early November. Seeding it too early in the season, like in August, can lead to heat stress and seedling diseases; when seeding it late in the season, the grass may not become fully established prior to the winter cold.

Applying the seed during the spring is not advisable because, although it will germinate, it has insufficient time to become established before the summer heat and dry conditions. Soil preparation is the most important aspect of caring for a fescue lawn. It prefers fertile, well-drained soils with a soil pH of 5.5 to 6.5. If the pH is low, you can apply lime at anytime during the year to raise it. Make sure you have the soil tested through Gwinnett Cooperative Extension to determine the pH and nutrient needs.

Most established fescue lawns need to be periodically reseeded since they have a tendency to thin out over time. Since our soils are mostly clay, they are easily compacted by rain, irrigation, foot traffic and the intense summer heat, which decreases the ability of the roots to grow, for air and water to penetrate into the soil.

To reduce compaction, use a core aeration machine with hollow tines which poke holes into the ground and pulls out small one to two inch long "cores." The deposition of the small cores of soil on top of the ground also assists in decomposing any thatch layers that have accumulated. Before aerating, mow the grass down to 11/2 inches to help improve the ease of aerating the soil and for seed to make soil contact.

When aerating, do so in a criss-cross direction by first going over the entire lawn, back and forth in one direction and then using the machine to go back and forth at right angles to the first series of trips. Aerators are often available at rental or garden centers.

The seed purchased should be of good quality to ensure a high percent of germination and minimal weed content, and should have this information listed on the tag. Using cheap seed can be quite expensive in the long run due to poor germination and purity. Make sure the seed is certified by the Georgia Crop Improvement Association (www.certifiedseed.org) with a certification tag on the seed bag.

Apply the seed to the fescue lawn at the rate of five pounds per 1,000 square feet. Resist the temptation to apply more seed since closely growing seedlings compete with each other for water and nutrients, as well as become susceptible to disease. One of the most commonly used fescue seed has been Kentucky-31. However, in more recent times, newer, improved cultivated varieties, with names such as "Southeast" or "Rebel" have come on the markets which are often more attractive cultivars and are referred to as "turf-type" tall fescues. These newer grasses have finer leaf blades, lower growth habit, darker green color, greater density and more shade and heat tolerance than K-31.

After over-seeding has been completed, the upper one inch of soil needs to be kept moist during the time the seed is germinating which usually requires a light application of water on a daily basis. As the seed comes up and begins to grow, cut back the watering to a couple of deep, thorough applications per week. Refrain from mowing for a couple of weeks after the seed has been applied, and then mow at a height of two to three inches. Never mow wet grass since this will damage the seedlings. With proper preparation and planning, and using the appropriate cultural methods to maintain the fescue plot, you will have an attractive and healthy fescue lawn giving you an exceptional lush, green carpet of grass throughout the year.

Timothy Daly is an agricultural and natural resource agent with Gwinnett Cooperative Extension. He can be reached at 678-377-4010 or tdaly@uga.edu.