While we often focus on lawn maintenance in the spring of the year we must also remember that preparation for winter should be part of our routine. Because Bermuda grass stops growing at temperatures below 60 degrees Fahrenheit, now is the time to be thinking about fall maintenance.
The bulk of work on a Bermuda grass lawn will happen around April. The application of fertilizer and pre-emergent is completed to protect against crabgrass and broadleaf weeds, and de-thatching or aeration can be done when the lawn is completely green. Further steps may be taken by adding post-emergent herbicides after the lawn is in full growth for control of knotweed, spurge, grasses and sedges but this is only necessary if a weed problem was apparent the previous summer. Fertilizer is also added at 1 pound nitrogen (N) per 1000 square feet and can be continued every 6-8 weeks in order to keep a lush, green and weed free lawn. These extra applications are not necessary to sustain the lawn but will give it a well-maintained look.
The biggest concern in fall is proper preparation of the plant for winter dormancy. Your grass needs to be as healthy as possible before it initiates dormancy at temperatures below 50 degrees F. A fall management program, or 'winterizing' routine, will help overcome cold-temperature stress and should be done in August or September.
When adding fertilizer in the fall, apply ? pound of nitrogen per thousand square feet in using a low nitrogen but high potassium fertilizer such as 5-5-10. This should be done at least 4 to 6 weeks before the first expected frost. Research indicates that late-season nitrogen fertilization alone does not contribute to the susceptibility of Bermuda grass to winterkill. The combination of nitrogen and vertical mowing or aeration in fall contributes to increased susceptibility to cold-weather injury. Don't make the mistake of verticutting in the fall. Deep vertical mowing of plant tissue will promote new growth of stolons and rhizomes creating fresh tissue that is susceptible to cold injury. This practice should be saved for spring and summer.
By September the mowing height should be raised ? inch to help prepare for winter dormancy. If winter is windy or warm the lawn will need water to prevent desiccation of plant tissue. Mother-nature may provide plenty of water but if not, a good soaking will be in order.
Liming can be done from September to December to allow time for the material to break down over winter or a quick release lime can be applied from February to May. The amount of this application should be based on soil test results.
Fall applications of potassium (K) at a rate of 1 pound per 1,000 square feet will help to support the root zone and produce a stronger plant with more rigid cells, purging water from the leaf tissue as the plant hardens off. To determine the amount of product to apply divide 100 by the third number in the fertilizer ratio. A 5-10-15 fertilizer would be 100 divided by 15 for 6.67 pounds of product per thousand square feet. If you are concerned with having a formal green lawn until frost you can apply iron sulfate. This will green up foliage but not produce new growth; however, this effect will not survive the winter.
It is also during September or November that you will want to apply pre-emergent to protect against any winter infestation of poa annua and annuals like chickweed and henbit. This is often combined with fertilizer and sold as a 'winterize' package. Winter will provide the opportunity to use glyphosate, glufosinate or diquat herbicides for non-selective control of all green plants. Make sure the Bermuda grass is completely dormant before using these products. If there is any green tissue on the grass, it may be injured.
As the maintenance cycle comes full circle in February, you will want to put down a broadleaf weed control. This will help control crabgrass, goose grass and foxtail and should be put down no later than the blooming of forsythia bushes.
Helpful Publication: Fresenburg, Brad and Travis Teuton. Managing Lawns and Turfgrass Publication MG10. University of Missouri Extension. September 2007. Helpful Sources: Jeff Higgins. Give bermudagrass sports turf proper fall management. Grounds Maintenance. 1999 Penton Media.; Patton, Aaron and John Boyd. Lawn Care Calendar -- Bermudagrass. FSA6121. University of Arkansas Division of Agriculture. Cooperative Extension. November 2008.
To determine the amount of fertilizer product required to apply 1.0 pound of nitrogen per thousand square feet, divide 100 by the first number in the fertilizer ratio. For example, for a 20-5-5 fertilizer divide 100 by 20. The result is 5 pounds of product per thousand square feet.
The Extension office is located in Kennett, Missouri at 101 South Main Street (the old bank) on the 2nd floor. Open Monday -- Friday or you can call 573-888-4722 if you have a question. University of Missouri Extension programs are open to all.
Sarah Denkler is a horticulture specialist
with University of Missouri Extension
in Dunklin County.