News Release Distributed 07/16/10

By LSU AgCenter horticulturists Dan Gill, Kyle Huffstickler and Allen Owings

Summer is prime growing season for lawns in Louisiana. Lawns that are not performing their best can be made better through the fall. If you did not fertilize your lawn during the spring, you still have time to fertilize and get your lawn in good shape prior to fall. But only keep with a fertility program through early to mid-August, and water your lawn deeply once or twice a week as needed.

Watch for chinch bugs in St. Augustine and Bermuda grass lawns, and if they turn up, treat them with an LSU AgCenter-recommended insecticide. Chinch bug problems show up as yellow-brown areas of the lawn during hot and dry weather. These insects extract plant juices from grass stems and crowns while pumping in toxic salivary fluids that disrupt the plant’s vascular system.

There is still time to dethatch Bermuda grass, zoysia and centipede grass through late July, if needed. Consider renting mechanical dethatchers for zoysia and Bermuda grass lawns. It might be better to hand rake out “thatchy” areas of centipede grass lawns because centipede grass can be slow to recover from aggressive dethatching. Fertilize and water lawns after dethatching. And keep in mind that St. Augustine grass is not as prone to thatch problems as other lawn grasses.

Centipede grass should receive its optional second and last fertilizing in late July or August. For centipede grass, apply only one-half pound of nitrogen per 1,000 square feet as a complete turf fertilizer – for example, three pounds of 17-0-17 or five pounds of 10-0-10 per 1,000 square feet. Other lawn grasses would need about twice this rate. A slow-release, turf-blend fertilizer is best and worth the extra cost. These types of fertilizers are widely available at garden centers and feed stores throughout the state.

Carpet grass only needs one fertilizing in spring. Fertilize St. Augustine grass, Bermuda grass and zoysia in June and again in early to mid-August with at least one pound of actual nitrogen per 1,000 square feet, for example, seven pounds of 13-13-13 or five pounds of 19-19-19 per 1,000 square feet.

Make sure lawns are getting adequate moisture during the summer. Centipede grass is the least tolerant lawn to drought, so make sure it receives adequate amounts of moisture, especially during dry periods.

If you intend to apply a winterizer on your lawn for fall, don’t just go by the name “winterizer” because it may be a northern type of fertilizer for a fescue-blend type of lawn. These types of winterizers are common at many stores. A true southern winterizer fertilizer should be low in nitrogen and high in potassium, or just use 0-0-60, which is muriate of potash.

You’ll need about one pound of potash – K₂O equivalent – per 1,000 square feet. You can apply this as 1½ pounds of muriate of potash. Apply all granular materials on a dry lawn, and water it in soon after application.

Weed management is difficult in St. Augustine grass and centipede grass lawns because herbicides can cause severe lawn injury when temperatures exceed 90 degrees. Limit applications to careful spot treatments to reduce lawn injury.

Visit LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is near the intersection of Burbank Drive and Nicholson Drive (Louisiana Highway 30) in Baton Rouge, across the street from the LSU baseball stadium. For more information, go to www.louisianahouse.org and www.lsuagcenter.com/lyn.