Summer is especially hard on cool season grasses like tall fescue and bluegrass. Cool-season grasses should begin to recover from the heat as the cooler temperatures of September and October arrive. If you have dead spots here and there or spots where the grass is thinning a bit, now is the time to renovate your lawn.
Follow these steps when renovating your cool-season lawn:
Step 1: Have the soil tested
The soil test is currently paid for by a tax on fertilizer, so why not take advantage of it? Soil sample boxes and forms can be acquired at your local office of NC Cooperative Extension. Many offices will also receive the sample and forward them on to the Agronomic Division of NCDA&CS. The publication “A Gardener’s Guide to Soil Testing” is available at most NC Cooperative Extension offices and online. This publication has information on how to take a good sample and how to read the test results when they come back. Test results should be back in one to two weeks this time of year.
Step 2: Select a high-quality seed variety
It may sound like I am trying to sell the higher-priced seed, but consider the following before you make a purchase. In the lower Piedmont, we are at the very edge of where cool-season grasses will grow and survive. The summers are long, hot, and dry. The grass selected needs to be one that was bred to survive these conditions. The higher-priced seed more often fits that description.
Step 3: Prepare the soil
Before you start, mow the lawn first so the seed can reach the soil. If you have bare spots, scratch up the area with a hard tine rake or a small cultivator. There is no need to till the soil deeply, just loosen the surface. In areas where the grass is thin, the soil will be fine the way it is. Loosening the soil in thin stands may do more damage to the existing grass. Aerating the soil with a plug type aerator is also helpful. If you are going to use the aerator, water the area well a day or two ahead of time to loosen the soil.
Step 4: Seed and fertilize
Before spreading seed, apply fertilizer according to the recommendations on the soil test report. If the report has not come back use a starter fertilizer high in phosphorus (the second number) to encourage good root growth. Bare spots will need to be seeded at the rate for new lawns according to what is on the package. Areas that are thin should receive about half that amount. Bare areas should be covered with a layer of wheat straw to shade the seed and keep it moist during germination. You should be able to see about 50% soil and 50% straw. Areas with thin turf will not need the straw. The existing turf will do the shading.
Step 5: Proper maintenance
After the seeds have been put down, the area should be watered. It is very important the seeds don’t dry out during the 7 to 10 day germination period. Light irrigation 3 or 4 times during the day is best until the seeds germinate. After germination, begin to reduce the frequency and increase the duration of the irrigation until you are watering once or twice a week to encourage deep roots. When grass is tall enough to be cut, be sure to use a mower with a sharp blade and only remove about 1/3 of the leaf blade at any one time (example: mow at 3” when grass reaches 4.5” tall).
For more information on maintaining or renovating any type of grass, visit www.turffiles.ncsu.edu and look for the lawn maintenance calendars or the publication “Carolina Lawns”.
Shawn Banks is a Horticulture Agent with the NC Cooperative Extension Service. You may reach him at firstname.lastname@example.org.