Spring has arrived and plants are beginning to break dormancy, but the home lawn may not be lush and green yet. Many homeowners have a centipede lawn. Centipede grass does not become green as quickly as some other warm-season turfgrasses. Temperature and day length are the two factors that influence when centipede grass comes out of dormancy and the rate at which the grass returns to its green color. There are other factors that can affect the health of the centipede lawn such as maintenance, insects, disease, and fertilization.
Problems with centipede grass lawns often develop three to five years after establishment. These problems can generally be related to mowing heights more than 2 inches high, annual nitrogen applications of more than 2 pounds per 1,000 square feet, or early spring or late fall fertilizations. Lawns with excessive thatch are also more likely to have received winter injury because of the extra distance between the stolons and the soil surface.
Excessive thatch can result from a lawn height greater than 2 inches and from over fertilization. Also, excessive nitrogen applications during last year’s growing season and/or fertilizer applications made too early in the spring makes the grass more susceptible to winter injury.
Insects could also be the source of the problem. Mole crickets and grubs can cause excessive root damage. During this time of the year, only the adult stage of the mole cricket is active. The adult is hard to eradicate, and now is not the appropriate time to treat them. Contact a lawn maintenance professional to make an application if they are causing excessive damage that cannot wait until June. June is the ideal time to treat for mole crickets due to their life cycle.
Disease is another factor that could be causing problems.
Take-all patch and large patch are common problems noticed in centipede grass. Some of the damage probably occurred last year. Proper identification of the disease is needed to determine the course of treatment.
Centipede grass is also susceptible to yellowing or iron chlorosis. The chlorosis may be caused by one or more of the following factors: excessive nitrogen or nitrogen applied during spring green-up; high soil pH or phosphorus levels; or excessive thatch caused by over-fertilization, irrigation, pesticide use or by mowing the lawn too high.
Iron chlorosis can be temporarily overcome by spraying 2 ounces of iron sulfate per 1,000 square feet or a chelated iron material according to label rates. An excessive application of iron will appear within a few hours as blackening of the leaf blades. The grass may take a few weeks to fully recover from such high rates of iron. The real solution is to determine and correct the cause of chlorosis.
Your lawn may be showing signs of a combination of the above mentioned factors. Try not to get over anxious with fertilizer application this spring; be patient. Wait until your lawn is at 100 percent green-up and the soil temperatures have risen (usually late April/early May).
Follow the management practices below to enhance the growth of your centipede grass lawn.
1. A fertilization program should be based on a soil test analysis. Fertilize lawns after spring green-up and again in mid-summer. Do not exceed 2 pounds of nitrogen per 1,000 square feet per year.
2. Mow your centipede lawn at a height of 1 to 1.5 inches. Try to avoid thatch buildup.
3. Irrigate during periods of drought stress. Apply enough water to wet the soil to a depth of 6 to 8 inches.
4. Identify insects and diagnose diseases; then treat accordingly.