Thomas J. Koske | 9/23/2005 2:47:34 AM
In September you’ll hear, "It's time to winterize your lawn," just as last spring you heard, "It's time to weed and feed." Yet, this practice may not be beneficial or even necessary, according to LSU AgCenter horticulturist Dr. Tom Koske.
To winterize warm-season turf means to slow down growth and boost plant potassium (K). Koske says winterizing in the late summer can be beneficial if soil fertility is low or if you have pushed a lot of growth with extra nitrogen (N). In those cases, you’ll want to build up the K in the soft plant tissues for a little extra tolerance to cold.
If you supplied adequate N and K all season long, extra K from winterizing will probably make no difference, the horticulturist points out. This is especially true with a moderate winter.
"The important steps to remember are to slow down fall grass growth and use a southern winterizer formula for our warm-season grasses," Koske says.
To slow grass growth, use little or no nitrogen after late summer. This practice also will cut back on brown patch disease. If extra green grass is desired in the fall, use a liquid iron (Fe) spray to get greening with little extra growth. Be aware that centipedegrass, however, does not always respond too well to foliar applied iron. The grass may burn.
"If you want to winterize, use the right stuff," Koske advises. Extra K can be applied alone in late summer-early fall as inexpensive muriate of potash. Apply 1 or 2 pounds of muriate per 1,000 square feet to a dry lawn and water it in to avoid salt burn.
A winterizing lawn food is fine, too, as long as the first number (N) is low and the third number (K) is high. This is a southern winterizing formula. Northern winterizing formulas are just the opposite with a high N and lower K.
"Northern formulas are wrong for our lawn grasses at this time of year," Koske says. "They spur fall growth and create more succulent turf that is more prone to disease and winter kill."
For more on winterizing, see "Winterizing Your Southern Lawn" on the www.lsuagcenter.com Web site. More information on lawn care is available at your local LSU AgCenter office. In addition, look for lawn & gardening and Get It Growing links in the LSU AgCenter Web site.