Pensacola News Journal

For: Saturday, Oct. 13, 2001

By: Daniel E. Mullins

Extension Horticulture Agent

Santa Rosa County

Let Your Lawn Go Dormant and Get a Grip

Lawn problems are number one when it comes to complaints that we hear from gardeners during the spring and summer months. I am thankful that the typically beautiful weather of fall is here, and I can get a break from diagnosing sick lawns.

Everyone wants a nice lawn, and it is possible – just more of a challenge under Gulf Coast conditions. Most of the lawn problems that we see are inflicted by the person maintaining the grass, not by some exotic insect or disease that can be magically cured with a special concoction. There are exceptions of course. Heavy chinch bug, spittlebug, sod webworm infestations or brown patch disease can kill entire sections unless treated.

A man brought some grass samples to the garden clinic a couple of weeks ago that really brought home this point. The squares of sod submitted for diagnosis exhibited the results of having been exposed to just about every possible wrong cultural practice.

Typically, we ask that two six-inch squares of sod be brought to our clinics. These squares should be from the margin of two different dead spots, containing about half dead and half live grass. By examining the leaves, stems and roots it is often possible to diagnose the problem and recommend corrective actions.

This particular sample provided an excellent opportunity to point out the results of improper maintenance and make recommendations for improvement. On the other hand, the lawn problem created was a source of added expense and frustration for this homeowner.

Allow me to review our findings when examining this grass in hopes that others might avoid such problems.

n The lawn was being mowed using a dull mower blade. This had resulted in a ragged appearance and grass blades that were split, instead of being cut smoothly. Disease organisms had gained entry through these splits and were working their way down toward the grass stems.

n This grass, which happened to be St. Augustine, was being mowed too low. A coarse textured grass such as this must be mowed relatively high in order to maintain good health.

The recommended cutting height for the standard St. Augustine varieties is 3 to 4 inches. If mowed too low, there is never enough leaf surface area to photosynthesize properly. In other words, a lawn that is mowed too low gradually starves to death for food that would have been furnished through photosynthesis if enough leaf surface was present.

n The client was watering every day. Such frequent irrigation had led to damage from both insects and disease. A shallow, weak root system was also created, making the plants less able to tolerate heat and other stress factors.

n Many different kinds of broadleaf weeds were found in these samples. All of the improper practices previously discussed had lead to weed infestation. The old cliché, “the best weed control is a thick, healthy lawn” certainly applied here. Any cultural practice that can cause turf to become sparse invites an infestation by weeds.

n He was applying too much of the wrong kind of fertilizer. This practice led to excessively lush, but weak growth that was less pest resistant and demanded much irrigation to keep the grass from wilting.

Obviously, most lawn disorders are brought on by extreme cultural practices: mowing too low, dull mower blades, fertilizing too heavily, watering too often, while applying too little water at each application.