A ground level image of a single-car garage door and some well-maintained lawn. Sitting on the lawn is a broadcast spreader.
Apply pre-emergent herbicides to lawns in fall to prevent winter weeds. Fall is also a great time to apply lime to adjust soil pH, if necessary.

Heather N. Kolich, ANR Agent, UGA Extension Forsyth County

While autumn is still a few weeks away, proper care in late summer and early fall helps your bermudagrass, centipedegrass, or zoysiagrass lawn enter dormancy at the appropriate time, protects against cold injury, prevents winter weeds, and reduces disease problems during spring green-up.

Stop applying nitrogen. Nitrogen stimulates growth, but as the active growing season comes to an end in August for warm-season grasses, we want to allow growth to slow down in preparation for dormancy. Fertilizing in September can delay dormancy long enough for warm-season turfgrass to suffer from cold injury. Nitrogen in the fall also sets lawns up for Spring Dead Spot. It’s ok to make a final application of nitrogen in August to very early September, but as days get shorter and nights grow cooler, let warm-season turfgrasses go through the natural processes to enter dormancy.

Adjust mowing height. The normal mowing height range for bermudagrass, centipedegrass, and zoysiagrass is 1-2 inches. If you’ve been mowing on the lower side, raise the mower blade up to cut at the 2-inch height.

Continue irrigation. Warm-season lawns still need an inch of water per week as they slow growth for dormancy. Watering deeply and less frequently encourages roots to grow deeper into the soil. If rainfall is sufficient, skip irrigation; overwatering encourages root rot and other turfgrass diseases.

Collect a soil sample for testing. Fall is an excellent time to apply lime if needed. Each species of warm-season turfgrass has a different optimal pH range. If soil pH is too low, dolomitic lime can be applied to raise it, but it’s a process that can take several months. A laboratory analysis is the only way to know how much lime is needed to create the desired change.

Apply pre-emergence herbicide. If you’ve had lawn weeds in the past, chances are strong that you’ve got weed seeds in the soil, just waiting for the temperature and moisture conditions to be right for growth. A pre-emergence herbicide prevents seed germination so that weeds don’t get a chance to grow into seedlings. It’s important to apply pre-emergence herbicides before soil temperatures cool to 55 degrees Fahrenheit, the point at which winter weed seeds can begin to germinate, or before nighttime air temperatures consistently dip below 60 degrees F. The UGA Weather Network (http://georgiaweather.net/) is a good resource for monitoring soil temperatures, rainfall, and other weather trends.

Pre-emergence herbicides contain various active ingredients and typically control several broadleaf annual weeds and some annual grass weeds. The products continue working in the soil for several weeks. Some products allow or recommend a second application 8-10 weeks after the initial treatment.

A pre-emergence herbicide that contains potassium as the carrier product will enhance winter hardiness in bermudagrass lawns. Look for pre-emergence herbicides that have 0-0-7 or something similar, with the first two numbers (for nitrogen and phosphorous) being zeros. Note that products containing atrazine should not be used on bermudagrass lawns. Refer to the Georgia Pest Management Handbook (https://ipm.uga.edu/georgia-pest-management-handbook/) for guidance on herbicide selection and application.

When using herbicides and other pesticides, always follow the directions on the product label – including using specified personal protection equipment. Application rates are legal limits that define the minimum amount at which the product is effective and the maximum amount at which the product is safe to use for you, your plants, wildlife, and the environment.

For lawn care calendars and information on soil testing, please visit the Forsyth County Extension website at https://extension.uga.edu/county-offices/forsyth.html.

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