Ronald Strahan, Koske, Thomas J. | 2/15/2007 11:29:15 PM
Spring is the time to begin working on a new southern grass lawn, and LSU AgCenter horticulturist Dr. Tom Koske has advice for those undertaking such a project. If seeding, remember that it takes quite a while to develop mature plant material that will over winter with best success. Bermudagrass will establish fastest form seed; the others may take more than 1 year of growing in. Even the fast bermuda seed should have at least 3 good months to grow in before early frosts. If you don't have the time, choose a vegetative type establishment of solid sod or plugs.
Koske says there are four distinct components of establishing turfgrass: clearing and grading to provide the desired contours and good surface drainage; soil preparation; planting; and watering and maintenance.
"The key to successful establishment of a home lawn is proper soil preparation," Koske says, adding, "You should prepare the soil the same way, whether you are planting by seed, sprigs, plugs or sod. It's hard to change your soil once you have sod on it."
The first element in soil preparation, according to Koske, is to remove all the debris from the area to be planted. "This includes rocks and bottles, as well as tree stumps and roots, which will eventually decay and leave depressions in the lawn," he says. Depressions collect water and weeds.
If you do extensive grading, Koske says to remove the topsoil to a side and replace it after the rough grading.
"The rough grading should conform to the final grade after the topsoil is added," he notes, explaining that a 1- to 2-percent slope (1 foot to 2 feet of fall per 100 feet) away from all buildings provides good surface drainage.
If you're installing internal drainage or irrigation systems, the best time to do it is during this stage of soil preparation.
The horticulturist adds that the subgrade may become compacted during construction and rough grading – especially if the ground is wet. Break up this compacted layer before proceeding, he advises.
Once the subgrade is established, respread the topsoil. Allow for at least 4 inches of depth after the soil has settled.
After the topsoil is spread and graded, add fertilizer and lime as indicated by a soil test.
"Thoroughly mix the lime and fertilizer with the top 3 inches of topsoil," Koske says. A general recommendation for a starter fertilizer is 10 pounds of a fertilizer, such as 6-24-24, per 1,000 square feet of lawn.
If you use a soluble source of nitrogen, do not apply more than 1 pound of nitrogen per 1,000 square feet. If you use a controlled release insoluble source of nitrogen, such as ureaformaldehyde, you can apply 2 pounds of nitrogen per 1,000 square feet before planting.
After the soil is prepared, grass can be planted by seeding, sprigging, plugging or sodding. If laying sod, lay it tight together – don't checkerboard the squares or you'll have a bumpy lawn. Then, be sure to follow through with watering and maintenance for two to four weeks after planting, Koske says.
"Be careful not to destroy the existing trees in the lawn," he cautions about the process of preparing and planting new grass. "Cutting a large percentage of a tree's roots during soil tillage can severely damage or kill it.
"Trees can be suffocated by covering the roots with 2 inches of soil," he says, advising that if soil is necessary at a tree base, construct a "tree well," which helps protect roots.
Everything has a season, and if establishing a warm-season grass from seed, spring and early summer is it. Plants growing from seed are juvenile and delicate. Even after several months, they may not have the mature storage structures that help them get through serious stress and long dormancy. An early, but not too early, start gives the new plants the best chance.
Planting southern grasses in late summer is best done with sod and vegetative material that is already mature and just needs to root.