Pensacola News Journal

For: Saturday, April 20, 2002

By: Daniel E. Mullins

Extension Horticulture Agent

Santa Rosa County

Lawn Maintenance Overkill is Hurting Centipede

Many centipede lawns are in bad shape this spring. Dead and yellow patches are common and in some cases, as much as half of the lawn is dead. Much of this damage is due to the use of improper maintenance practices.

We are literally killing our centipede with kindness, especially where fertilization is involved. Until recently this species of grass was known as the “poor man’s grass,” because it is known to require less fertilizer and water than most other species.

Though centipede, like other plants, needs proper levels of nutrients to do its best, overzealous management can hurt more than it helps. Properly maintained centipede is light green and slow growing, not dark green and lush. If mowing is required more often than every 10 to 14 days, then it is being grown too fast.

Centipede does not tolerate repeated heavy applications of high nitrogen containing fertilizer. Researchers have found that this practice contributes to the development of centipede decline.

Centipede Lawn Fertilization Checklist

• Don’t apply fertilizer until warm spring weather is here to stay. Fertilizing before the last frost invites disaster.

• Choose the fertilizer type carefully. There are many brands and formulations and making a choice can be confusing. First look for one that has 30 to 50 percent of the total nitrogen in a slow or controlled release form. The product should contain about as much total potassium (the third number on the bag) as it does nitrogen.

• Avoid the use of high phosphorus containing products. Phosphorus is the middle number on most 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.

• A fertilizer with an approximate ratio of 3-1-3, nitrogen to phosphorus to potassium, is highly recommended. This is a ratio of elements, not the actual analysis that you will find on the garden center shelf. Examples of some fertilizers that would fit this ratio include 18-5-18, 12-4-8 and 15-5-15. Avoid those that are very high in nitrogen, yet contain low percentages of potassium.

• I have never seen a centipede lawn that starved to death, so only a little fertilizer is required. Two light, split applications spaced several weeks apart are better than one heavy application. The above analyses for example, would be applied at only 3 to 4 pounds per one thousand square feet of area if split applications are made. This amounts to only about 25 pounds for the average sized lawn.

• Have a complete soil test done every three years so that soil nutrient levels can be altered, if needed.

• Calibrate the fertilizer spreader and make sure that the right amount is being applied in a uniform pattern.

• Water immediately after the application in order to activate the fertilizer and prevent burning.

The suggestions listed above apply to the long term health of centipedegrass. In the meantime, homeowners with sick grass should get a diagnosis and take measures to correct the immediate problem. Contact your local garden center, lawn professional or Extension agent for recommendations.

Question of the Week: I planted cucumbers this spring and they grew for a while, before shriveling up and dying. What’s the problem.

Answer: Cucumbers are very sensitive to cold soil and low air temperatures. The stems or roots probably rotted. Try planting again but this time use treated seed, plant only about one inch deep and don’t plant in exactly the same spot where earlier seedlings have died.