Hand holding seeds over lawn to begin overseeding lawn treatment.

What Is Overseeding & Does it Work?

Is your lawn looking a little patchy, brown, or otherwise lackluster? It’s likely suffering from drought, disease, or insect damage. It could also be that some grass species don’t overwinter well, or are of older varieties. 

One solution that may help bring your lawn back to life is overseeding.

Continuing to thicken and diversify your grass stand is an important cultural method. If you haven’t overseeded your lawn in a while, it could naturally be thin and bare because of not doing so. In the same way, when you kill weeds but don’t replace the space with new grass, you’re omitting a large part of the process that helps develop a healthy, thick lawn that can naturally crowd out weeds.

What Is Overseeding?

Overseeding is adding new grass seed over your already existing turf—without turning the soil. By overseeding a lawn, you can thicken grass density, introduce enhanced varieties of grass to your lawn’s microclimate, and improve color to an ideal lush green. 

In addition, different grasses help “hedge your bets” against insect, weeds, and disease pressures. Some grasses, for example, are more resistant to certain diseases, so diversifying your stand helps you protect against the unforeseen.  Diversity also helps sun-loving grasses thrive in the sun, while shade-loving grasses will stick to the shady spots

Overseeding is typically performed after core aeration, a process that helps improve good seed-to-soil contact and allows water and nutrients to more quickly, and efficiently, penetrate the soil—all of which can greatly improve the overall quality of your lawn.

When Is the Best Time to Overseed a Lawn?

The answer to that question depends on where you live and what type of grass you are sowing. Here in Minnesota, we recommend overseeding in late summer to early October—when the weather is moderate enough to provide the perfect germination balance of warm soil and cooler air temperature. 

Fall seeding is better than spring because spring seeding has high weed competition, and the immature grass roots will struggle with the stresses of summer (i.e., their root structure is weak and immature and you will have to baby it along in a hot/dry summer).  

Immature grass can overwinter much better than oversummer. Sowing in the fall season allows for the grass to start growing. Then, you’ll want to continue maturing next spring to be fully prepared for summer stress. 

Note: Species like tall fescue should be sown in late summer, while fine fescue blends can do well when planted in early October. 

Aeration and overseeding should be done annually, always as a good cultural method. It’s especially important to aerate and oversee new sod installations for at least 6-years. This ensures the sod soil and existing soil mix well, and it also helps diversify the sod grass.  

Most sod is 100% Kentucky bluegrass, which is 100% one cultivar. Diversifying that stands to better protect against insects, disease ,and weeds.

How To Overseed a Lawn

STEP 1: PREP THE GRASS

• Cut the lawn as normal. 

• Any clipping or debris can be recycled, as they will provide free nutrients to the germinating seed.

STEP 2: AERATE

• Using an aerator tool (or landscape service), pull up plugs of soil to create small holes across the lawn. This creates new “pores” in the soil, in which seeds can settle to germinate.

STEP 3: SEED

• Select the correct seed for your lawn conditions and region, and follow the package directions.

• Use a seed spreader to evenly and efficiently distribute.

STEP 4: WATER & MAINTAIN

  • Keeping the seeded area moist continually for the first 1-2 weeks is the key to new seeding success. It is necessary to water often enough that the soil does not dry out and not so much that puddles form (usually 10-15 minutes of watering per area). 
  • On average, water 2 times daily, between 6-9 am and 2-6pm. On hot, sunny days you may have to water 3 times a day.
    • If the soil dries out, the seed will dry out and die because its short roots do not reach deeply yet. 
  • After 2 weeks, reduce the frequency of watering 1-2 times per week, once per day for 30-60 minutes of watering per area.
  • Within 2-4 weeks, you will notice new grass growing. New growth takes 12-18 months to mature into a dense lawn.
  • Begin mowing new areas when they reach 4”in height.
    • Mow with a sharp blade at a setting of 3”. 
    • Mow often enough so that the clippings do not form a blanket and smother the new grass. For the same reason, please do not allow fallen leaves or pine needles to cover the lawn.

Note: Watering your lawn is a time-consuming commitment, so please be sure you will be able to maintain the watering needs of your new seeding. And while watering may be the single most important factor that will determine the success or failure of your seeding, lawn care including fertilization, weed control, and related services are essential to a healthy, green lawn.

5 Benefits of Overseeding a Lawn

  1. Improves grass thickness, color, and overall appearance
  2. Repels disease,insects, and weeds
  3. Increase optimal root growth 
  4. Reduces erosion
  5. No chemicals or pesticides necessary!

Think Your Lawn May Benefit from Overseeding?

To learn more about aeration and seeding services, or other organic lawn solutions, reach out to our lawn experts at Organic Lawns by LUNSETH today! 

Contact us, so we can assess your lawn’s needs and get you a fast quote!