Maintaining Cool-Season Grasses

Ready to fertilize. (Courtesy: Lori Tripenfeldas at

Ready to fertilize.
(Courtesy: Lori Tripenfeldas at

In a previous blog I discussed facts about cool-season grasses. These types of grasses are ideal for use in the middle to northern half of the United States. These grasses commonly have two growing seasons –- spring and fall. In addition, some species go dormant through the winter for between one and four months depending on the location and the harshness of the winter. The turf is designed to tolerate cold weather.

Here are some tips on maintaining these types of grasses.

Cool-season grasses leave their winter dormancy period in early spring when they turn a lush green color. If the lawn is established, then fertilization with nitrogen is necessary. Experts suggest that you use a slow release fertilizer because it is better for the environment and will feed the lawn longer than a traditional fertilizer.

If crabgrass was a problem during the previous year, then you may want to apply a crabgrass pre-emergent with the fertilizer.

It is imperative that you follow instructions on the fertilizer’s bag. Experts also suggest that you use a lower spreader setting than recommended and make several light passes of your lawn. If you select a spreader setting that is too high, then too much of the fertilizer could be used.

Mowing of tall fescue and Kentucky Bluegrass cool-season grasses should be performed once or twice a week in the spring. The optimum mowing height is 2.5-inches to 3.5-inches. Remove only one-third of the grass height. If the grass is very tall, then experts recommend that you mow once at a high setting and a second time at a lower setting a few days later. Experts suggest that you mulch clippings. This action will rejuvenate the soil with nutrients. Bag clippings only if they pile up on top of the grass and cannot be removed by any other method.

You should use a sharp mower blade because less stress is put on the plant and it prevents fungus from appearing that can damage the lawn during the summer.

Whether you have to water or not throughout the summer depends on climate conditions and your expectations. If you desire a lush, perfect lawn throughout the summer, then you will probably need to water more often. Tall fescue and Kentucky Bluegrass turn dormant to survive extreme drought.

Water your lawn during the early hours of the day. Many experts suggest that such an action should occur from 4 a.m. to noon. There is less evaporation loss and less water is necessary because it is cooler during that period of time. This process also reduces the possibility of fungus because the grass can dry in the afternoon. If your region of the country experiences night time temperatures more than 70 degrees, then use a liquid fungicide as a preventative measure. Most fungicides will protect your lawn for three-to-four weeks per application.

Grubs could become an issue as they feed on the roots of your lawn during the spring and fall. Apply chemical grub control to deal with the problem. The best time to apply the substance is in July when the grubs are laying their eggs. Read the instructions on how to use the insecticide to determine if watering is necessary to get the chemicals into the soil after application.

Fall is a good time to aerate cool-season lawns because it can relieve compaction and permits air to get to the roots of the grass. However, mow the lawn very low before aerating so that it is easier to remove the cores. To assure a thorough job pass the aerator along different directions of your lawn.

Once the aerating is finished you can over seed and fertilize the lawn. The process of over seeding will fill areas that may have died during the previous year. Be sure to use seed that is recommended for your location. If your lawn features tall fescue, then over seed at one pound per 1000 square feet; if your lawn features Kentucky Bluegrass, then over seed at a pound per 1000 square feet.

Tall fescue seed will germinate in about seven to 12 days; Kentucky Bluegrass seed will do so in 14 to 30 days. Fertilize after seeding to be certain that the new grass gets all the nutrients it will need to grow.

As noted, the lawn will need to be fertilized. If you over seed, then you may want to test the soil to ascertain that there is a proper amount of phosphorous. If not, then consider applying some. If you haven’t over seeded, then nitrogen fertilizer will be sufficient. Follow the directions given for fertilizing in the spring that appears above.

Remove leaves from your lawn within a few days so that they can’t block sunlight from getting to the grass.

The winter is the time that the cool-season grasses are dormant. During this time the grass will turn a greenish yellow and stay like that until spring. Don’t worry. This is normal. It’s the grass’ way to preserve energy.

About Robert Janis

Written by Robert Janis for LawnEq - Your specialists for Lawn Mower Parts and Small Engine Parts. We offer genuine premium OEM parts for Land Pride, Toro and many more dependable manufacturers.