This article originally ran in the Ruston Daily Leader on October 11, 2011.
It’s about that time that we will start seeing signs that say, “It’s Time to Winterize Your Lawn.” But in reality, the sign should read, “Take a soil sample to see if you really need to winterize your lawn.” We need to remember that just because the sign says to do something that it doesn’t necessarily mean that it's accurate.
The main nutrient in a fertilizer for winterizing your lawn is potassium. Potassium seems to enhance cold tolerance in summer lawns and reduces harm from damaging frosts. Be aware that an excessively high rate of potassium fertilizer can cause foliar burn, or may compete with other nutrients for uptake. Excessive potassium is especially known to affect how much magnesium is taken up by turf grass, which will result in a lighter green turf color. Always apply granular fertilizers onto dry foliage to reduce the likelihood of salt burn.
If selecting a winterizer fertilizer containing nitrogen, be sure that the nitrogen content is low, compared to the potassium, which is represented by the third number in the analysis. This will allow you to apply appropriate amounts of potassium without applying excessive amounts of nitrogen. When too much nitrogen is applied too late and too heavily to warm-season turf grass, nitrogen fertilizer will promote shoot growth at the same time the plant's metabolism is slowing. This results in a depletion of carbohydrates and stress on the plant. The new, tender shoots are also less tolerant of cold temperatures. Furthermore, the additional nitrogen will be available to cool-season weeds and may increase the incidence of large patch disease, which is very prevalent in the fall.
The only way to truly know if you need to apply a winterizer is to have a soil analysis done on a sample of your soil to see what the potassium content of your soil is. If the content is low, you may need to winterize. If the content is optimum to high, then you may actually be causing yourself more harm than good by putting out a winterizer. Typically when potassium levels to require winterizing, I don’t usually recommend more than 1 pound of potash per 1000 square feet of lawn.
The soil tests are simple to collect and cost only 10 dollars to have the analysis run. If you believe that winterizing may be for you, give me a call and let me get you the forms and mailing boxes so that you can have a test done before doing something that may not be needed at all.
Please contact me for more information.
The LSU AgCenter and the LSU College of Agriculture