Too much fertilizer kills centipedegrass

Fertilize centipedegrass sparingly, accept its light crabapple green color and low maintenance requirements.

Are you dissatisfied with your centipedegrass lawn this spring? Do you have dead areas within your lawn that failed to turn green or areas that are weak, open and thinning with intermingled yellow grass blades? If so, you’re most likely dealing with a common problem. It’s called centipedegrass decline.

This condition involves a complex of incorrect management practices and sometimes involves nematodes (microscopic worms in the root area), ground pearls (scale-like insects in the root area) and fungi. But the major contributing factor to centipedegrass decline is over fertilization.

As a matter of fact, if you wanted to induce this condition in a centipedegrass yard, all you’d need to do is to be a little heavy handed with fertilizer. And in a year or two, sections of the lawn would begin to show the classic symptoms of decline – patches that begin to die at spring green up or shortly thereafter. It’s that simple. Centipedegrass does not and will not tolerate very much nitrogen!

Fertilize centipedegrass sparingly, accept its light crabapple green color and low maintenance requirements.

Pay close attention to the following checklist when fertilizing centipedegrass.

• Don’t apply fertilizer until warm spring weather is here to stay. Mid-April is the earliest that you should fertilize centipedegrass. You may even skip a year or two in fertilizing a centipedegrass lawn.
• Choose a fertilizer with 30 to 50 percent of the total nitrogen in a slow or controlled release form. The product should contain about as much total potassium (third number) as it does nitrogen (first number).
• Avoid fertilizers with high nitrogen yet containing a low percentage of potassium.
• Avoid the use of high nitrogen or high phosphorus containing products. Phosphorus is the middle number on fertilizer containers. Excessively high levels of this element in the soil have also been implicated in centipede decline and the inability of the grass to take up iron and other micronutrients.

• Only a little fertilizer is required with centipedegrass. Two light, split applications spaced several weeks apart are better than one heavy application. Always be light handed when fertilizing a centipedegrass lawn.
• Never apply a high nitrogen fertilizer after July.
• Water immediately after the application in order to activate the fertilizer and prevent burning.

For more information on how to grow a Florida lawn, contact the University of Florida/IFAS Extension Office in your County or visit http://hort.ifas.ufl.edu/yourfloridalawn.

Larry Williams is the Extension horticulture agent with the Okaloosa County Cooperative Extension Service, University of Florida. Contact Larry at 689-5850 or email lwilliams@myokaloosa.com.