UNIVERSITY PARK, Pa. -- Late summer or early fall is the best time to plant new lawns. But for homeowners who need to do some springtime seeding, a turfgrass specialist in Penn State's College of Agricultural Sciences offers some suggestions.
"The seed to use depends on whether you want to repair damaged areas or put in a new lawn," says Peter Landschoot, associate professor of turfgrass science.
Seeding dead patches
To seed dead patches or thicken your lawn, Landschoot suggests using perennial ryegrass. "Perennial ryegrass is a dark green, fine-textured species that's very compatible with Kentucky bluegrass," he says. "Chances are you already have some in your lawn. Perennial ryegrass germinates and establishes quickly. You could put light traffic on it within 8 to 10 weeks after planting."
Unlike Kentucky bluegrass, which takes two weeks to germinate and a few months to establish, perennial ryegrass should mature before the hot, dry summer months, when new seedlings are susceptible to drought.
When buying ryegrass, Landschoot suggests avoiding "annual ryegrass," also known as "Italian ryegrass," which is one of the most commonly sold grass seeds. It's also found in some professional landscapers' mixes. "Annual ryegrass may establish a few days earlier than other ryegrass," he says, "but most people don't like its coarse, wide-bladed texture. It also thins out quickly. After two to three years, you're back to ground zero."
Landschoot also suggests avoiding the perennial ryegrass variety 'Lynn,' "a common, inexpensive and notoriously bad seed that fades from a lawn over several years."
Heavily shaded areas
Homeowners who have a large spreading tree under which the lawn has thinned out may need to reseed with specialty grasses.
"Heavy shade and grass don't go together," Landschoot says. "But if the site receives more than three hours of direct sunlight each day, you probably can get a fine fescue to establish. Red, creeping red or Chewing's fescue are all shade-tolerant grasses that do well provided you have well-drained soils."
For best results, heavily shaded areas should be planted in September, and the soil should be tilled and raked as if starting a new lawn. "The grass needs time to establish before the trees leaf up and start shading it again the following summer," he says.
If the area stays wet, Landschoot suggests fixing the drainage problem. "Not many landscape plants -- including grasses -- do well in poorly drained soils.
"For areas that get fewer than three hours of direct sun, you probably should stick to a shade-tolerant ground cover, such as myrtle or pachysandra," he says.
Establishing a new lawn
Since most yards are not completely sunny, or completely shaded, Landschoot suggests using a mix of species when starting a new lawn. "Having some diversity in your seed mix makes sure a lawn will thrive under the different conditions," he says.
Sun (with some shade). For a sunny lawn with some trees, Landschoot suggests a mix with 40 to 60 percent Kentucky bluegrass, 30 to 40 percent fine fescues and 10 to 20 percent perennial ryegrass. "The Kentucky bluegrass and ryegrass will predominate in the sunny areas and the fine fescues in the shade," he says.
Another good choice for a sunny lawn is tall fescue. "Tall fescue is a very drought-tolerant, low maintenance species," Landschoot says. "During a drought, it will be the only green grass in the lawn. But tall fescue should be planted alone. Its light-green color and coarse texture don't blend well with the finer turf grasses, such as Kentucky bluegrass, ryegrass and fine fescue."
Landschoot suggests buying a good quality, "turf type" tall fescue from a reputable dealer. "Stay away from the variety 'Kentucky 31,'" he says. "This grass forms large, coarse clumps in lawns, and most people are very dissatisfied."
Shade (with some sun). For a shaded lawn with some sunny areas, Landchoot suggests a mix containing more fine fescue. "A mix with 50 to 60 percent fine fescues, 30 to 40 percent Kentucky bluegrass and 10 to 20 percent perennial ryegrass should do well," he says.
"New lawns are hard work," Landschoot says. "If you're going to go to all the trouble and expense to put in a new lawn, don't scrimp on seed. Do your homework."
For information on preparing a new lawn, see the Penn State College of Agricultural Sciences publications, "Turfgrass Seed and Seed Mixtures" and "Turfgrass Establishment." Single copies are available free of charge from your county Penn State Cooperative Extension office, or by calling the College of Agricultural Sciences Publications Distribution Center at 814-865-6713.
Landschoot stresses that buyers shouldn't simply rely on brand names, or choose a seed just because the bag says it's a sun or shade mix. "You should read the label to find out the grass species included, the percentage of each seed and the date of the germination test," he says. "For best results, the germination test date should be within nine months of purchase, and the percent germination should be at least 80 percent -- preferably higher."
"A lot of companies that sell turfgrass seed in Pennsylvania market something called 'Penn State Mix,'" he adds. "Penn State has absolutely nothing to do with these companies, the makeup of the mix or the seed. These mixes can contain just about anything -- sometimes you'll find it's a good mix, but sometimes it's very poor quality."
Landschoot suggests storing leftover seed in a cool, dry place and using it within one year. "Seed can pick up moisture on a cement floor," he says. "The best place to store it is on a shelf, in a garage where the temperature stays below the 90s.
"Be sure to use a mouse-proof container," he adds. "Mice love seed."
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EDITORS: For more information, contact Peter Landschoot at 814-863-1017.
Contacts: Kim Dionis KDionis@psu.edu 814-863-2703 814-865-1068 fax