Fall Reseeding of Tall Fescue

Fescue lawns benefit from fall reseeding

Brian Jervis: Ask a Master Gardener

Saturday, September 5, 2015 1

Q: A large area of my fescue has died and needs to be reseeded. This happened in spite of a lot of rain. Can this be prevented? How do I reseed? Troy, Tulsa

A: The loss of tall fescue turfgrass in summer is a recurring event for most people. It is worse with hot and dry summers but can occur with excessive rain as well. Normally fescue can briefly take standing water, but when the ground is saturated, oxygen is forced out and the roots suffocate. Then along comes the stress of heat, which fescue tolerates poorly. This combination of events can kill fescue. Another threat to fescue comes from a common fungus called “brown patch,” which is destructive.

After this series of events in summer, it is time to reseed in fall, ideally from mid-September through mid-October. Reseeding of fescue can be done either in spring or fall, but the spring-seeded grass usually dies in summer due to the lack of root development. Grasses seeded in fall have a more mature root system to withstand the following summer.

As far as how to reseed, there are several steps involved. Detailed information is available in the Master Gardener’s office in Tulsa or online.

Seed selection is an important decision — both the type of seed and the quality. Remember with seeds you get what you pay for — buy high-quality weed-free seeds. OSU feels there are many good fescue varieties and no one variety is “best.” It recommends using a blend of three or more types of fescues alone or mixed in with bluegrass, another cool-season grass. Mixed with fescue, the two grasses seem to compensate for each other’s weaknesses.

To minimize loss of fescue next summer, obtain the Master Gardeners’ information sheets on lawn care and follow recommendations about watering, fertilization and mowing.

Steps for reseeding fescue Lawns

1. For existing lawns, identify and correct factors causing poor performance. Start with a soil test to see what nutrients and soil acidity corrections may be needed.

2. Make a decision as to what type of seed you wish to plant and purchase beforehand.

3. Buy a “starter” fertilizer, best based on soil test. Use only nutrients needed. Do not use phosphorus containing fertilizer unless a soil test indicates a need.

4. Remove undesirable grasses and weeds

5. Loosen the soil by hand or machine, adding fertilizer and organic compost as needed. This is important, as all soils have a crust which should be broken for seeds to thrive.

6. Sow the proper amount of seed to get good coverage, avoid excess seeding. More is not better.

7. Irrigate as needed to keep top of soil constantly moist until seedlings are 2 inches tall.

8. Irrigate less often and more deeply at 2 inches to establish deep roots.

9. Mow with a sharp bladed mower when 3 inches tall.

10. If needed, control broadleaved weeds with a 2,4-D type herbicide after third mowing.

Garden tips

Fall webworms are now prevalent. These are the dense webs one sees on the limb tips of some trees, especially pecans. The caterpillars remain within the webs to feed on leaves, expanding as new leaves are needed. Control can be as simple as pruning out, if the tree size permits. Insecticides can be helpful, but most people tolerate the infestation, realizing the damage is mostly aesthetic and the tree will survive quite well. If an insecticide is used, consider an organic product called Bacillus thuringiensis, or Bt. It is safe for you, your pets and the environment.

Now is a good time to submit a soil sample to the OSU Extension office for testing. Do this before reseeding fescue or creating a garden bed this fall. Call the Master Gardener office at 918-746-3701 for instructions.

Tall fescue should be mowed at 3 inches and up to 3½ inches if it grows under heavier shade. Don’t fertilize fescue lawns until it cools later this month, then fertilize again in November.