Seeding a New Cool Season Turfgrass
by Don Janssen, Extension Educator
The best time to seed a new cool season turfgrass lawn is late August through early September. Cool night temperatures favor rapid germination and establishment. The key to success, however, is often proper site preparation.
Before you disturb the soil, kill perennial and broadleaf weeds with a recommended non-selective herbicide such as glyphosate (Roundup or Kleenup). It is very effective against troublesome perennial weeds, but it will kill any green, growing plant, so users need to be careful to keep it from contacting landscape ornamentals, nearby turf areas, and flower or vegetable gardens.
The next step is to remove stumps, rocks, roots, buried wood or other debris.
If you need to make a grade change -- to encourage water to run away from the house, for instance, or to eliminate a low, wet spot in the yard -- first remove the topsoil and stockpile it nearby. Fill the low spot and replace the topsoil.
Avoid making grade changes around established trees. Even seemingly minor changes can damage roots and weaken or kill trees.
This is also the time to improve your topsoil. Improve sandy or clay soils by working several inches of compost or fibrous peat into them. Add one inch compost to each four to six inches of soil disturbed.
Apply a starter fertilizer and work into the top 2 inches of the soil. Allow the topsoil to settle for a while.
To seed the area, divide the seed into two equal parts and apply half of it in one direction -- say, east to west -- and half at a right angle to that. Rake lightly with the back of a leaf rake to mix the seed into the top 1/8 to 1/3 inch of soil -- don't bury it. Then roll the seedbed to assure good contact between the seed and the soil.
Water as often as necessary to keep the area evenly moist until the grass emerges and starts to establish. Reduce irrigation intervals as the grass becomes established.
If your new lawn is to be sodded rather than seeded, site preparation is the same except that the site should be deeply watered (to a depth of 6 inches) a couple days before the sod is put down. Lay the sod within 24 hours of its harvest, if possible. Stagger the ends of the sod pieces like bricks and do not stretch the sod pieces -- they will shrink as they dry and gaps will develop. Deep watering may be needed daily until the sod is well rooted.
Sod can be laid anytime the site can be prepared, but fall is an ideal time because the usually cool, moist weather is conducive to grass plant growth.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office