Q: I have several dead spots of various sizes in my centipede lawn. I don't think insects or disease is killing it. What do you think has happened and what should I do?
A: You are experiencing what a lot of folks with centipede lawns have seen this spring: Winter kill.
There are several reasons why this happens.
A primary culprit is the mild winter, which resulted in more growth and use of stored plant food than normal.
Worse, we had 70 percent to 80 percent green-up when a late frost occurred in early April. This can be devastating to centipede, especially if fertilizer was applied before the last frost.
Compounding the problem is drought. The net effect is the exhaustion of food reserves, which leads to turf loss.
Another possibility is a thatch problem.
Many homeowners have said that when they walked over their lawns last year the grass was thick and cushiony. This results from mowing the grass too high, and that means thatch.
Stolons grow in the thatch layer and away from the soil surface, which makes them more sensitive to temperature and moisture fluctuations.
All of the above conditions can be complicated by herbicides, insects (especially grubworms and mole crickets), and by diseases that may have caused injury in the fall or spring.
Here are some tips for maintaining healthy centipede in the lawn:
To avoid a late frost, wait until at least May 1 to fertilize. Never use more than 1 to 1´ pounds of nitrogen during the entire growing season. Use a fertilizer that is fairly low in nitrogen, such as 16-4-8, or a centipede fertilizer that has an analysis of 15-0-15.
Centipede should not be mowed above a 1´-inch height. Higher cuts combined with excess nitrogen lead to excess thatch.
To help prevent excessive thatch, you might dethatch your lawn every two to four years by renting a dethatcher or by lightly dressing the top (¨-inch layer) with a weed-free topsoil (not sand). It would probably be a good idea to aerate your lawn occasionally (every year or two) to help get water, nutrients and air to the roots.
Watch for insects and disease. Never water your grass between 4 and 7 p.m. Irrigate as infrequently as possible to develop a deeper root system.
As for the dead areas you have, rake the dead grass out. Depending on how big they are, you could let the grass spread back into those areas, or you could give it some help by planting sod, sprigs or seed.
Sid Mullis is director of the University of Georgia Extension Service office for Richmond County. Call him at 821-2349, or send e-mail to firstname.lastname@example.org. The offices that serve Richmond and Columbia counties have a Web page at www.griffin.peachnet.edu/ga/columbia.