Tips for establishing or renovating a cool-season lawn
Many lawns were decimated by the armyworm infestation we experienced in late summer.
So you may be planning to reseed your cool-season lawn this fall. The mid-September through early October time frame in Oklahoma typically has near-ideal day/night temperature combinations for germination of cool-season grasses.
Sodding of these grasses also is appropriate at this time.
The best temperatures for germination of cool-season grasses are when we experience a mid-80s day and upper-50s/low 60s night. When you see evening temperatures from the upper-50s to mid-70s, it’s time to seed cool-season lawns.
A damp seed bed is important during the first few days after seeding. If you are an Oklahoma City resident and are concerned about irrigating every day (rather than every other day) when trying to establish cool-season grass, go to the Oklahoma City Utilities website at okc.gov/utilities and fill out a newly installed landscape watering variance application.
Choosing your grass seed can be confusing. There are many satisfactory performing tall fescue varieties. These include, but are not limited, to Crossfire II, Houndog V, Millenium, Rembrandt,
Plantation to name just a few. There are actually dozens of good performers.
Consider using a blend or mix of coolseason grasses. A blend is a combination of two or more varieties (like tall fescue) within the same species. A mix is two or more species combined.
Blends and mixes are beneficial in cool-season lawns as they broaden the genetic diversity present. In theory, this decreases the likelihood that your lawn will be completely wiped out by a single disease or single insect infestation.
Tall fescues are best in medium to light shade. In lightly shaded areas, mixtures of tall fescue and Kentucky bluegrass can sometimes work best. While Kentucky bluegrass is generally not as shade tolerant as tall fescue, it still has some shade tolerance, and it has improved disease resistance over that of tall fescue.
These mixtures often will have Kentucky bluegrass present at 5% to 10% by weight and tall fescue at 90% to 95%. There are 10 times as many bluegrass seeds in a pound of bluegrass as there are tall fescue seeds present in a pound of fescue, so we use about 10 times less bluegrass seed to get to a 50/50 species count.
Be sure to choose a turf type rather than a forage type tall fescue.
Forage type fescues include Fawn and Alta. General purpose soil stabilizer types include the old K-31, Kentucky 31, KY 31, they get used as a forage and as a lawn, but these variations on Kentucky 31 are not true turf-type tall fescue despite what the marketing message on the seed bag might say. Turf-types are selected for improved color, texture, density, slower vertical leaf expansion rate and other important characteristics for lawn use.
There is seldom any benefit and there often is detriment created by mixes of cool-season perennial grasses with annual or Italian ryegrass. Yet, if you scout the store shelves, you will find these mixes.
Annual ryegrass simply competes with the cool-season perennial grasses in the mix in the cool portion of the year when good growth can take place, and then annual ryegrass, having taken its fair share of the lawn, dies out in the heat.
There are several fact sheets from OSU available to assist you and they can be found at ousfacts.okstate.edu. Fact sheet HLA-6418 covers turfgrass selection, while HLA-6419 covers the establishment (planting method) and HLA-6420 covers the mainstream longterm maintenance practices (mowing, fertilization, irrigation, etc.). A newer fact sheet, HLA-6608, addresses managing turfgrass in the shade.