If you overseeded your lawn or athletic fields last fall, you should help your turf out of that "fix," says LSU Agricultural Center horticulturist Dr. Tom Koske. The warm-season grass will be trying to re-establish itself as the cool-season, overseeded grass grows strong.
This competition is a dilemma for those who overseeded. "It all boils down to a battle between grasses, and we normally want the permanent grass to win," the horticulturist says.
In some cases, the overseed is encouraged to hang on for some late spring athletic tournament, but that is usually at the expense of the bermuda underneath. If you are able, take the winter grass off early and allow for a good green-up of the warm-season turf in mid spring.
Because Louisiana weather is inconsistent, and residents never know what combination of temperatures and soil moisture levels will be experienced, achieving an "ideal" transition is difficult. For example, without a warm and dry spring, the cool-season overseeded grass hangs on.
In an ideal transition, the perennial ryegrass completely disappears just as the bermudagrass has fully greened up. But, when the ryegrass dies out faster than the bermudagrass fills in, the result is poor.
In addition, the newer heat-disease- and drought-tolerant varieties of perennial ryegrass, which are being used for overseeding, may survive farther into the spring or summer than older cultivars. Thus, while these newer ryegrass varieties provide more attractive turf during winter, they also create problems with spring transition.
To hasten the removal of overseed, Koske advises applying simazine, metsulfuron or imazaquin when turf is at or near full green-up. If it is applied before that time, it should be applied several weeks before green-up. Read the label for precise application. Most places in south Louisiana already have started that green-up period for this year, he says.
Pronamide, foramsulfuron or rimsulfuron herbicide also can be used on bermudagrass, providing a gentle transition with mid-spring application.
Homeowners may try to keep their lawns a little drier and use a weed-and-feed product with a simazine or atrazine herbicide component.
No matter how it is accomplished, when the overseed first fades, begin or step up your nitrogen fertility program to minimize thin, transitional turf, Koske advises.
Related yard and garden topics are available by contacting an extension agent in your parish LSU AgCenter office. Also, look for Gardening and Get It Growing links in the Feature section of the LSU AgCenter Web site: www.lsuagcenter.com.