Lawn renovation – cool season grasses

Lawn renovation – cool season grasses




What is lawn renovation?

For lawns that have suffered severe damage from insects, disease, weeds or drought, or if you’re just looking for a re-do with an enhanced cultivar, a complete lawn renovation is often the best option.

In this article we will discuss renovation using the two most popular two season grasses – Kentucky Bluegrass and Tall Fescue.

Unlike overseeding, a renovation involves killing your entire stand of grass and starting with a clean slate. As with all seeding projects, success depends upon 3 factors:

1. Seed to soil contact

In order for grass to successfully establish, the seed must be in direct contact with the soil so that the roots may grow into the soil and extract nutrients. Seed that sits on top of thatch or dead grass has a poor chance of establishment.

2. Heat

Fescue and Kentucky Bluegrass seed germinate best when temperatures outside hover between 78-85 degrees. Within this range, fescue germination will take place in 4-5 days. Kentucky Bluegrass may take up to 3 weeks to reach 80% germination.

3. Water

After seed has been applied and watered, it must be kept continuously moist until germination. Allowing the seed to dry can result in a complete loss. Grass seed must be watered 3-4 times a day for 15 minutes at a time until germination takes place. The goal is to keep the seed moist, not to soak the soil. After germination, the frequency of watering should be gradually reduced and the quantity of water applied at each watering gradually increased.

When should renovation be done?

Renovation of  lawns North of the Mason-Dixon line should be done mid-August. Renovation of cool-season lawns in the transition zone should be done around Labor Day. This timing gives the new grass the time it needs to establish so it can survive the following summer.

Spring is a very bad time to renovate due to weed pressure and the limited time available to the grass to establish before the summer heat. Seeding projects in the spring generally result in a weedy mess and wasted time and money.

Planning ahead for renovation

It pays to plan ahead. If you’re applying a pre-emergent in the spring, make sure that you apply at a rate that will not extend coverage into and interfere with your seeding project. Most pre-emergent herbicides prevent ALL seed from successfully germinating.

Preparing for renovation

Having everything ready when the time comes can make the difference between success and failure. You will need:

  • The square footage of your lawn. Tools such as this can be of great help.
  • Seed. Follow the seed producer’s recommended seeded rates.
  • Glyphosate(RoundUp). Do not use “extended control” type herbicides which contain pre-emergent and will prevent the seed from germinating.
  • If you do not have an irrigation system, you will need hoses, a multi-zone controller and impact sprinklers.
  • A broadcast spreader.
  • Starter fertilizer.
  • Optional: granular fungicide.
  • Optional: Tenacity herbicide.
  • A push mower. If you have a riding mower, it may be too rough to use on the new seedlings.


Renovation involves killing all existing grass and weeds to create the perfect bed for a new, uniform fallowlawn that will be the envy of the neighborhood. The process of killing all existing vegetation is called fallowing. Begin 3 weeks before your target seeding date by spraying your entire lawn area with glyphosate. Water for 15-20 minutes on a daily basis for the next 7 days to sprout more weeds. Spray with glyphosate again and continue to water daily for 10 days. Spray newly germinated weeds with glyphosate once again. The process will deplete the seed bank and reduce the amount of weeds that will germinate along with your grass seed.


  1. Cut the (dead)lawn at your mower’s lowest setting.
  2. Remove all clipping and debris from the lawn. Use a rake to remove as much of the thatch and dead grass as possible. Remember, we need good seed to soil contact.
  3. Using the broadcast spreader, spread the seed at the recommended rate slightly overlapping each pass. Do not over-apply – grass that is planted too dense is unable to develop properly and looks like doll hair.
  4. Using the broadcast spreader, apply the starter fertilizer at the rate indicated on the bag.
  5. Consider applying a granular fungicide  like Bayer Fungus Control at seeding time. The heat and frequent water creates perfect conditions for fungus which can destroy new seedlings in a matter of days.
  6. Consider spraying Tenacity at pre-emergent rates at seeding time to further suppress weed germination.
  7. You are now ready to water. Program your controller to water each zone 3-4 times a day for 15 minutes.(No sprinkler system? A Orbit 4 zone watering system may come in handy)

Post-germination care


New lawns should be watered:

  • 15 minutes twice daily for the first 7 days after germination. Avoid watering in the evening as it greatly increases the risk of disease.
  • 20 minutes daily for the following 14 days.
  • 30 minutes every 3 days for the next 2 weeks.
  • 45 minutes every 5 days for the next 2 weeks.
  • Slowly work your way towards the deep and infrequent watering schedule.


Mow the grass when it first  reaches 3.5″ inches down to 2″. Make subsequent cuts to 2.5″ for the first month when the grass reaches 3.5″. Maintain the lawn at 3″ after the first month throughout fall to encourage lateral growth.


New lawns should be fed with 1 pound of Nitrogen per thousand sq feet monthly through fall using a lawn fertilizer that is high in Nitrogen. Make the first post-starter fertilizer application 4 weeks after seeding.


Disease is common in newly seeded lawns due to new grass being susceptible to fungus. Keep a vigilant eye on the grass and be ready to act swiftly and apply a fungicide at the first sign of trouble – it may only take a few days to wipe out an entire renovation.

Weed control

Wait 30 days after germination to spray any weeds with herbicides. Young grass can be damaged along with the weeds if sprayed too early.

Wait 60 days to apply pre-emergents – they can interfere with root development in young grass.

Final words

Remember to use your common sense and listen to what the grass is telling you. If you see signs of drought stress, water. If you see signs of disease, act swiftly. If the grass does not look ready for cutting ,wait a little longer. The most important factor that determines the success or failure of a renovation project is YOU.

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