Spring has arrived, and plants are beginning to break dormancy. But the home lawn might not be lush and green yet.
Many homeowners have a centipede lawn. Centipede does not become green as quickly as some other warm-season turf grasses. Temperature and day length are the two factors that influence when centipede comes out of dormancy and the rate at which the grass regains its green color.
Other factors can also affect the health of the centipede lawn, such as maintenance, insects, disease and fertilization.
Problems with centipede lawns often develop three to five years after establishment. These problems generally result from mowing heights of more than 2 inches, 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 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 or fertilizer applications too early in the spring make the grass more susceptible to winter injury.
Insects could also be a 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 adults are hard to eradicate, and now is not the time to treat them. Contact a lawn-maintenance professional to make an application if the excessive damage cannot wait until June. The mole crickets’ life cycle makes June the ideal time to treat for them.
Disease could also be a problem. Take-all patch and large patch are common problems in centipede. Some of the damage probably occurred last year. Proper identification of the disease is needed to determine treatment.
Centipede is also susceptible to yellowing or iron chlorosis. The chlorosis may be caused by one or more of the following: 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 mowing too high.
Iron chlorosis can be overcome temporarily 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 might 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 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 or early May).
Follow these management practices to enhance the growth of your centipede lawn:
1. A fertilization program should be based on a soil test analysis. Fertilize lawns after spring green-up and again in midsummer. 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.
For more information on caring for lawns in Georgia, see the University of Georgia Extension turfgrass Web site at www.georgiaturf.com.