As autumn breezes in, we embrace the cooler temperatures—a fresh welcome from the oppressive highs in August—and look forward to decelerating our lawn and garden chores. October, after all, is peak season for college football. My husband, like many others, has made it quite clear that his complete, undivided attention is strictly reserved for his favorite SEC teams on football-season Saturdays, leaving no room for interference from wives, children, or pets. As you can see, lawn care didn’t have a chance in that list. Although warm-season grasses like St. Augustine, centipede, bermuda, and zoysia have begun to slow their growth for the year, some fall maintenance is required to ensure healthy lawns through winter and spring. By following a simple checklist—or playbook—for the fall, you can score a winning lawn and still have time left on the clock for plenty of college football.
First and Ten
Get a running start on weed control this fall by applying both preemergent and postemergent herbicides. Cool-season weeds like annual bluegrass, chickweed, and henbit are nothing short of a nuisance in winter lawns, while remnants of summer pests like dollarweed and Dichondra linger, unswerving, in acrimonious attempts to reseed with a vengeance next spring. While mowing a few times from late fall through early spring often helps with weed abatement, you may find your best management is through chemical warfare. First determine which type of lawn you have, as well as any weeds that may be loitering; for proper identification, consider bringing samples to your local garden center. Unfortunately, there is not one chemical that treats every weed; so depending on the weeds in your lawn, you may have to purchase multiple herbicides and make more than one application. Make sure the chemicals are listed for use on your lawn, and follow the label’s suggested rates for application; more does not mean better. Prevent existing broadleaf weeds from returning next spring by killing them now with products like 2,4-D, atrazine, or Fertilome Weed Free Zone. Eradicate any germinating weed seeds before they come up with preemergent herbicides like Hi-Yield Dimension, Gallery, or Greenlight Crabgrass Preventer. Do not apply preemergent herbicides though, if you plan to overseed your lawn with rye grass.
Most warm-season grasses in Louisiana will be completely or nearly dormant by mid to late November or December. Lawns will no doubt benefit from winterizers high in potassium. The term “winterize” refers to retarding plant growth, while strengthening levels of potassium, so as to toughen plant tissues for winter freezes. Winterizers improve cold hardiness, stem strength, and disease resistance. Remember, the grass must be actively growing to intake nutrients; the best time to winterize is mid-September through October. The first number listed in the analysis of these fertilizers, nitrogen, should be zero or very small, because fertilizers high in nitrogen would stimulate lush fall growth, increasing your lawn’s susceptibility to winter damage and diseases. The percentage of potash (which yields potassium) is the third number listed in the fertilizer, and it should be the highest. Winterizers best suited for our area have an analysis of 0-0-20 or 10-0-14. For best results, apply the winterizer over dry foliage, so as to reduce salt burn, and water it in if no rain is expected. Maintain adequate moisture levels in the fall, and clear fallen leaves from the lawn’s surface; extended periods of heavy leaf cover reduces the turf’s ability to photosynthesize and generate a carbohydrate reserve for storage during dormancy.
If you’ve noticed trouble spots in your lawn this spring and summer, but can’t quite pinpoint the problem, it may be time to have your soil tested. Understanding your soil’s makeup is an imperative step to acquiring a healthy lawn. Fall and early winter prove perfect for testing soil; not only will you beat the spring rush but fall testing allows more time to locate and apply any amendments needed. Lime for instance, which is required to raise the pH, takes several months to completely react to reduce soil acidity, and may burn foliage if applied in hot weather. Fall soil tests can also exhibit precisely how well your lawn performed during the past growing season. Optimal test values in the fall should manifest mid-range to show that your fertility program was sufficient, but not too strong or weak. Excessive fertility causes a buildup of nutrients, ultimately leading to growth problems or groundwater pollution. Likewise, inadequate fertility shows low to very low fall values, denoting that your lawn had run out of good nutrients before the end of the growing season, causing a weakened turf.
Basic soil test kits are often sold at local garden centers, but for more reliable and comprehensive results, check with your county agriculture agent. The LSU AgCenter, for example, offers services in which they analyze potassium, phosphorus, calcium, magnesium, and pH, among other values in their routine soil test. Soil sample boxes can be picked up and dropped off on the LSU campus in Baton Rouge, or at participating garden centers. For more information on soil testing, visit lsuagcenter.com.
Make it a Sack
Keep in mind that autumn is also ideal for fungal diseases and insects. “Large patch” (formerly called brown patch), caused by the soil-borne fungus Rhizoctonia solani, is the disease most prevalent on St. Augustine, along with other warm-season turfgrasses like Bermuda, centipede, and zoysia. Most active in October, November, and even early December in south Louisiana, large patch thrives in cool, rainy weather. As its name suggests, large patch is characterized by large, circular, irregularly shaped patches of diseased turf that can severely damage, and sometimes kill, portions of your lawn if not readily treated. Most often, large patch results in thinned areas of turf, eagerly invaded by weeds; edges of the patches display a yellow to orange cast that later turns tan or brown.
Spread can be rapid, so gain control quickly with the help of lawn-listed fungicides like Fertilome F-Stop or Fertilome Liquid Systemic Fungicide. Depending on the amount of cool fall weather and the frequency of rainfall, you’ll need to make at least two applications in the fall, with the first being in mid to late September, and the second a month later in mid to late October. Should conditions remain favorable for disease in November and early December, additional applications may be necessary to ensure healthy dormancy and lush spring “green-up.” Inhibit turf disease during the spring by making follow-up applications in March as well, once your lawn begins to flush.
Chinch bugs, almost the reverse setback of brown patch, prosper in lawns during hot, dry weather, especially in late September and October. These ant-size insects thrive by sucking the sap from the grass, causing it to dry out and die; affected blades often appear to be rolled up lengthwise. Because chinch bugs kill the turf, prompt treatment is crucial to minimize damage.
Extend the green color of your lawn through winter by overseeding with rye grass. Both annual and perennial ryes are suitable for Louisiana winters and can be overseeded in October or early to mid November. Remember that both types die when the weather gets hot, allowing your established warm-season turf to take over.
This fall, don’t fumble your chance at a healthy lawn. As the weather cools and growth rates slow, take the added precautions and extra steps for your turf, and have a winning lawn next year.