Thomas J. Koske | 4/21/2006 12:01:53 AM
Starting a lawn from seed is a tough proposition even when all things are done right. Poor fertility, too much or too little moisture, rain washouts, ants, weeds and disease all can cause havoc during establishment.
"What we don't need is poor quality seed on top of all those initial pressures," says LSU AgCenter horticulturist Dr. Tom Koske.
Starting a lawn from seed is an option for bermuda, centipede and carpet grasses. Seed quality is determined by genetic purity, crop or species purity and germination. These can be reviewed on the seed analysis tag that is associated with that seed lot and source.
Genetic purity should describe the type of grass, such as bermudagrass, and the cultivar name of the grass type. A lot number may help with tracing back a package of seed from it's source.
The purity of the seed lot is presented as percent of pure seed, weed seed, other crop seed and inert matter. Pure seed is the actual type you would want to buy (for example, Riviera Bermudagrass). Weed seed and other crop seed are other kinds of seed present that you do not want and should try to avoid. Inert matter is just filler, like sand.
Germination percentage tells how much of the pure seed is actually alive and available for establishment. Not all the seed present will germinate, and older seed is lower in germination. There should be a test date or date tested to show when these evaluations were done.
Other less important items may appear on the tag, such as seed vendor, place of origin, percent hard seed (germination resistant), seed treatments (if present) and noxious seed, which is also weed seed.
When cost per acre is of concern, and several sources of seed are available, calculate the cost of any bag of seed by determining the percent pure live seed (PLS). Multiply the pure seed percentage by the decimal percentage of germination. An example of 54 percent pure seed with a germination of 85 percent has a PLS of 45.9 percent. Thus, this seed bag has only 45.9 percent of the weight as true-to-type seed that will germinate (PLS). When planting larger areas, the cost of seed becomes significant.
"Evaluating the seed quality can tell you what kind of deal you are getting and what kind of results to expect," Koske says.
For additional advice on caring for your lawn and landscape, contact a county agent in your parish office of the LSU AgCenter.