Since the early 1980's I've planted and overseeded thousands of fescue grass lawns. One of the most important things to consider when establishing a fescue lawn is choosing the type and variety of fescue you'll plant.
What type of seed?
When planting or overseeding a fescue lawn, you'll want to choose a variety of fescue grass that performs well in your area. I don't usually recommend Kentucky 31 Fescue because it requires a higher mowing height during summer to keep it from "burning out" and is best suited for use in pastures. I always recommend a turf-type fescue.
When overseeding a Fescue lawn, it is not absolutely necessary to overseed with the same variety or name brand of seed that was used when your lawn was originally planted. Often, the variety you first planted may no longer be available. So, if you can't find the type you want try another variety!
Best planting time
Fescue seed is best planted in early to mid fall. This allows the seedlings to establish themselves before winter and then benefit from the spring root flush. The more extensive the root system is before summer the more resistant to drought your lawn will be. That means less watering. If you missed the fall planting season, the second best time to plant a fescue lawn is in early spring.
Before You Plant...
Check soil pH
Fescue grass thrives in a slightly acidic to neutral soil ranging between 6.5 and 7.0 on the pH scale. If you have an existing fescue lawn and it's looked nice and green, but has thinned a little over summer due to heat, chances are your soil pH is fine. On the other hand, if your fescue grass looks light green or yellowish you might want to test the soil pH. If you are planting a new lawn from scratch I would heavily recommend testing soil pH before planting. You can go ahead and plant your seed, but the soil test will tell you what if any product might need to be applied to adjust the pH.
Testing Soil pH Soil pH is a measurement of the alkalinity or acidity of soil and is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline. If you're unsure about the pH of your soil, or whwther or not it is suitable for growing Blue Star Creeper, it's a good idea to test the pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil Sulfur, Aluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions.
Learn More: What is Soil pH and How To Adjust It?
Amending the Soil
Whether planting a new lawn or overseeding, if your soil is dense clay you might consider using soil amendments such as compost, sand or other soil conditioners applied to the surface of the soil. You can also broadcast gypsum over the lawn area, which is a soil softener. When planting a new lawn you'll want to till these amendments into the soil.
Mow turf
If overseeding, mow existing turf to under 2 inches in height. This will allow seedlings time to sprout and mature some before the lawn needs mowing again.
Planting Instructions
Before broadcasting seed over your lawn, aeration of or tilling the soil is highly recommended.
When planting a new fescue lawn from scratch you'll get the best results by tilling the soil to a depth of 6 inches. Then rake smooth. If you have a large lawn you might want to consider hiring a landscape contractor to do the grading and soil preparation.
Aeration is most commonly done when overseeding an existing fescue lawn. Aeration allows seeds to drop in holes where plugs have been removed, reducing the possibility of washing and facilitating stronger root growth of seedlings. Aeration also allows fertilizer or organic matter applied to get to the roots and water to soak better into the soil.
When overseeding a fescue lawn it is best to use a mechanical "core-type" power aerator that will remove and disperse soil plugs (2 to 3" in length) randomly atop the ground. Core-type power aerators can be rented from your local tool rental store. Make two or more passes over the area to be reseeded.
TIP: If there's been little rainfall or irrigation and the soil is dry and hard, it's a good idea to soak the soil to a depth of 2 inches the evening prior to the day you will aerate. This helps the aerator pluggers to dig deeper and extract a longer plug.
How much seed?
If you choose a turf-type fescue seed, which is what I highly recommend, you'll want to broadcast the seed at the following rates.
New Lawn
Broadcast 8 pounds of turf-type fescue seed per 1,000 square feet of lawn area.
Overseeding
When overseeding an existing lawn, the amount of seed you broadcast will depend on how much of your existing grass survived the summer. If you lost about 50% of the lawn grass over summer you'll want to spread about 4 pounds of seed per 1,000 square feet of lawn area. If you lost only 25% of the lawn grass over the summer, you'll want to spread 2 pounds per 1,000 square feet over the lawn area.
IMPORTANT! Though it may be tempting to pour on the seed real heavy, if you're existing fescue lawn is full and lush you do not need to overseed. Too much grass and roots will compete for space, which can cause summer "die-out." Stick to the spreading rates mentioned above.
Spreading the seed
After aerating or preparing the seed bed, use a walk-behind or shoulder-type rotary spreader to broadcast the seed over the the lawn area. Broadcasting the seed first allows you to actually see where the seed is falling on the ground, ensuring even distribution and coverage.
Using a walk-behind rotary spreader, or shoulder spreader, start by broadcasting a band of seed around of the perimeter of the area to be sowed. Then make two passes over the interior lawn area. Make the passes in opposite directions to ensure good coverage. Spread a little extra seed in bare spots.
Fertilize and lime
After broadcasting seed, you'll want to apply a lawn starter fertilizer with a high-phosphorus content (the middle number). Follow instructions on bag for application rates.
If you tested for soil pH and results showed you need to apply pelletized lime to "sweeten" the soil do so after broadcasting fertilizer.
Mulch
Finally, follow up by applying a thin coat (just enough to cover the soil) of wheat straw or hay to bare areas when overseeding and to cover the entire lawn are when starting a new lawn from scratch. Mulch helps to retain moisture for quicker germination of seed, and also helps to preventing seed from washing.
Care of Seedlings
The most critical need of seedlings is water. To maximize the germination rate of the seed, soak your lawn on the same day you sow the seeds. Avoid watering so much at one time that it causes run-off, which could wash seeds away. Thereafter, be sure you to apply enough water to moisten the soil to a depth of one inch.
Wait to mow until seedlings have reached a height of 5 inches or so. At that time, mow grass to a height of 3.5 to 4 inches. Never remove more than 1/3 the height of the grass during a mowing.