Cool-season lawns
Amy Jordan, Special to the Gazette
Thursday, September 2, 2010
September is here, and it is time to think about lawns; cool-season lawns, that is. Whether you need to renovate, reestablish or simply implement or improve cultural practices, now is the time.
It’s a great time to fertilize grass such as tall fescue. These lawns should receive 1 pound of actual nitrogen per 1,000 square feet. To do this, measure the square footage of your yard. Then calculate how much fertilizer you will need to apply.
For instance, for a fertilizer with the analysis 20-5-5, it contains 20 percent actual nitrogen, so you will need to apply 5 pounds of this material to get 1 pound of actual nitrogen per 1,000 square feet.
A rotary or drop spreader could be used; the easiest way to ensure even application is to set the spreader on a low setting, measure out the total amount of fertilizer you will need for the yard, and make several passes over the yard until all of the material has been distributed.
Water the lawn after fertilizing with at least 1/4 inch of water if rainfall does not occur within 24 hours. (Do not water after applying a weed-and-feed type of fertilizer/herbicide combination).
This is also a good time to aerate a lawn to relieve compaction. Compaction can be a problem in lawns that have a lot of traffic, such as in areas where children play or in lawns with dogs, especially big dogs. Core aerators remove cores of soil and deposit them on the soil surface, where they gradually break down. Aeration improves water and nutrient infiltration and increases the oxygen supply to roots.
Renovation, or overseeding, could be done to improve a partial stand of turf. September is the best time to seed because seeds germinate and grow rapidly in the warm soil with time to become well-established before winter.
Cut the existing grass at 1 to 1 1/2 inches and bag or rake the clippings. It might be a good idea to aerate the lawn before seeding if the soil is compacted. A vertical slicing machine with thin fixed blades should also be used to ensure good seed/soil contact. Apply fertilizer based on a soil test or use a starter fertilizer.
Overseed at a rate of 3 to 4 pounds per 1,000 square feet for tall fescue, or 1 to 2 pounds per 1,000 square feet for Kentucky bluegrass. In this area, tall fescue will generally perform better than Kentucky bluegrass. Also, a turf-type tall-fescue blend will make a more-attractive, less-weedy lawn than K-31, but K-31 is less expensive and more drought-tolerant.
If only a few spots need to be reseeded, they can be prepared with a hand rake or pronged cultivator. Sow the seed uniformly by hand and spread a thin layer of soil over the seed or work it in with a rake. Keep the soil surface moist until the seed has germinated.
If the current stand of turf is very poor or if there are problems with drainage or grade, re-establishment would be an option. This involves destroying the current turf and correcting soil problems. Then add organic matter and fertilizer (based on a soil test or a starter fertilizer) and till the soil after to a depth of 10 to 12 inches or as deeply as possible. Allow the soil to settle for a few days, then do a final grading.
Read the label and choose a high quality seed (preferably less than 0.5 percent “other crop” or “weed” seed). Use a seeding rate of 6 to 8 pounds per 1,000 square feet for tall fescue. Blend the seed into the soil with a hand rake. Thoroughly soak the seedbed to a depth of several inches, then keep the seedbed continually moist with frequent light sprinkling until the seeds have germinated.
As the roots develop and grow deeper into the soil, water less frequently but soak more thoroughly until a normal watering schedule is established. Begin mowing as soon as the grass has reached a height of 3 inches with a sharp mower blade set at a height of 2 inches. Continue mowing at a height of 2 inches through the last mowing of the season.
• Amy Jordan is a horticulturist with K-State Research and Extension in Lyon County.