Overseeding and Fescue Maintenance

Creating and developing a beautiful, thick fescue lawn is hardly ever by accident. It requires a well thought out strategy and patience. Fall is the most important time in the development of a dense, thick fescue lawn. Actions taken in the fall (September/October) will determine the level of success or failure that you see in your fescue lawn the following season. Many folks believe that the end of summer marks the end of lawn care season, however the reality is that the end of summer marks the beginning of the real lawn care season.

Several things must happen in the fall to ensure that you have a thick, dense fescue lawn to enjoy the following season.

The first thing that must be addressed as the temperatures turn cooler in the fall is to re-seed the lawn (if the lawn is a cool season turf). Generally, the best time to over-seed fescue lawns is when nighttime temperatures are consistently below 70 degrees. In addition to over-seeding, the application of a pre-emergent herbicide should be made 4-6 weeks after over-seeding germination.

While daytime temperatures are important and play a role in plant establishment, more important are the nighttime temperatures. Cooler nights allow the soil to radiate heat into the atmosphere, thereby cooling the subsurface of the soil. Fescue can struggle in the hot, humid summers that we have here in the south.

Cooler soil is beneficial to fescue in several ways:

  1. it allows for more aggressive root growth and development from new seedlings and encourages an overall healthier plant
  2. allows for recovery by the plant from stresses incurred throughout the previous day (mowing, high temperatures, etc.)
  3. encourages the plant to reach maturity at its own pace, thereby growing a stronger plant that is more capable of resisting stress from the environment and people

This is precisely why fescue sown in the spring (when soil temps are rising) does not generally make it through the summer months. There simply is no time to reach maturity and the process is rushed.

The first thing to remember when deciding to over-seed your existing fescue lawn is to get the timing right. While trying to determine the appropriate date to begin the process, it would be wise to also begin looking for the right seed mixture. That’s right, mixture. Mixtures, or blends, take several varieties of fescue seed and combine them to provide a genetically superior stand of turf once established. Taking several fescue seed varieties allows the best parts, the strengths if you will, of those strains to shine through.

It is possible to get genetically pure fescue seed from distributors; however genetically pure seed is just that pure as it relates to one grass species. This, while it sounds good, is a weak option. Pure seed is not as genetically protected as certified fescue seed mixtures or blends are. Mixes contain several varieties of seed, all certified, and afford the consumer the benefits of multiple genetic codes.

Certified fescue seed mixtures/blends:

  1. have proven to be more genetically diverse,
  2. are able to withstand more environmental stresses,
  3. preform better in challenging environments
  4. provide better results to homeowners that do not have the time or resources to invest heavily into professionally managed turf care

That is a lot of words just for me to tell you that certified seed mixtures are the best way to go for the vast majority of homeowners.

Once the mixture and date have been determined, it is time to prepare the site for seeding:

  1. Mow the existing grass low, rake or blow off any debris, and dethatch if you can (you can rent these machines at most equipment rental stores).
  2. After the prep work is done, it is time to sow the seed. Make sure that your spreader is calibrated properly (most over-seeding rates fall in the #5-7/ thousand square feet range).
  3. Set the spreader to one half of the recommended over-seeding rate and make passes over the desired are in a north/south pattern, next repeat the process (again at one half the recommended rate) in an east/west pattern. The pattern change helps to ensure thorough coverage and good seed dispersion.
  4. Once the seed is down, a light topdressing of compost is advised to ensure good seed to soil contact (crucial for germination) and a light watering.

After the process is complete, keep the area watered for 7-10 days multiple times per day (as needed based on environmental conditions (shade, wind, temperature, etc.) making sure to keep the top layer of soil moist, reduce applied water as the new grass grows, eventually getting down to once every 2-3 days or as needed only. After establishment, fescue will need approximately 1-1.5″ of irrigation or natural rainfall each week. Only apply water to supplement natural precipitation.

Refrain from mowing the newly seeded area until the grass is approximately 3-5 inches tall. Fertilize with a balanced fertilizer 2-3 weeks after the first mowing.

For more information about lawn care techniques and methods, contact Crossroads Turf for a personalized consultation.