How to Overseed a Lawn

by | Lawn Tips

One of the most overlooked practices for a lush, beautiful lawn is overseeding. If your yard is healthy and full, you may not need to overseed your lawn. However, if your lawn is thinning or if other grasses are sprouting, overseeding is an ideal remedy for both issues.

Learning how to overseed a lawn will help you improve your lawn’s vitality and give you the lush lawn you want. Read on to learn how to overseed your lawn.

What is Overseeding?

Overseeding involves planting grass seed directly into an existing lawn without turning over or digging holes in the soil. But what’s the value of overseeding?

Overseeding is perhaps the easiest way to fill in bare patches in your yard. These patches could be a result of various factors, including harsh weather, animals, or stationary toys. It also helps enhance the density of your lawn, preventing weeds from spreading. 

Additionally, it makes your lawn look uniform. Overall, overseeding a lawn is essential for keeping it healthy. It’s important to know how to overseed a lawn correctly to avoid damaging it. 

When Should You Overseed Your Lawn?

Like most lawn care practices, overseeding requires proper timing. Otherwise, you’ll end up wasting your money, time, and effort, and the results will be uninspiring. So, what’s the best time to overseed a lawn?

For cool-season grasses, overseeding is best done in late summer or early fall. Overseeding during this period ensures that the young grass has at least two months to become well-established before temperatures drop too low and undermine healthy growth.

In the spring, the young grasses will have a few more months to develop deeper roots before the hot summer season arrives. Other reasons to overseed your lawn in the fall include:

  • minimizing competition from weeds like foxtail and crabgrass
  • warm soil temperatures promote healthy seed germination
  • cool air temperatures promote healthy grass growth
  • sufficient rain and soil moisture

How To Overseed a Lawn: A Step-by-Step Guide

What You Need

  • Aerator (optional)
  • Lawnmower
  • Rake
  • Soil test kit (optional)
  • Seed spreader
  • Fertilizer spreader
  • Hose
  • Sprinkler

Step 1: Aerate the Soil

This process involves creating holes in the soil to help water, oxygen, and essential nutrients reach the new grass seeds and the roots of the old grass. If your lawn has thatch, consider aerating it before overseeding. Aeration ensures that the seeds you use in overseeding reach the soil and germinate effectively. 

Step 2: Mow and Rake the Lawn

Mow your lawn shorter than usual to help the grass seed reach the soil more easily. Bag the clippings to prevent them from coming between the ground and grass seed. After mowing, rake the lawn to eliminate dead grass, sticks, rocks, and other unwanted debris.

Besides removing any barriers between the seeds and the soil, raking also helps loosen the dirt to promote successful seeding and germination. 

Step 3: Amend the Soil

Soil amendment involves adding specific nutrients and minerals to the soil to make it more favorable for particular plants and grasses. If your lawn hasn’t been flourishing as expected, you might want to perform a soil test to determine the soil type and acidity. With this test, you’ll find out what kinds of amendments to use on the soil for the grass to thrive. If your soil is fertile and has a neutral pH, adding nutrients is often unnecessary.

Step 4: Add the Grass Seed

Put grass seeds into a seed spreader, then spread approximately 16 seeds per square inch of soil. If you can’t find a spreader, spreading the seeds by hand can still work.

Make sure you use a grass seed that is suitable for your region or climate. The seed should also complement the existing grass. You might want to check the plant hardiness zone map of Canada to determine the average local temperature and choose the ideal grass type.

It’s best to use grass seed that has been evaluated by the National Turf Evaluation Program. Such seeds have undergone rigorous tests and proved to be drought-, disease-, and pest-resistant.

Step 5: Apply Fertilizer

Select the right fertilizer, and using a fertilizer spreader, start by scattering it around the lawn perimeter to ensure it reaches the edges. Then, spread the fertilizer following a mowing pattern until you fertilize the entire lawn.

Step 6: Water the Lawn

The lawn requires watering for a short time every day to promote healthy germination. The best time to water your lawn is in the morning, as it maximizes the water absorption. The evaporation rate is high in the afternoon and evening, meaning you’ll need to use more water for the best results.

Be careful not to overwater the lawn. Otherwise, you may wash the seeds away, undermine germination, or promote thatch development. Overwatering also encourages weeds and fungus growth.

Lawn Maintenance After Overseeding

Follow these tips to promote effective germination and healthy growth after overseeding your lawn.

Keep the Grass Seed Moist

The newly spread grass seeds require moisture to germinate. Sprinkle the soil lightly at least twice a day to keep it moist, but not excessively wet. Consider reducing the amount of water when the grass begins to sprout.

Avoid soaking the soil repeatedly, as it often causes root rot disease. As the grass grows, let the soil dry a little before watering again.

Consider Covering the Seeds

The existing grass usually offers cover and shade for the new seeds. However, if your lawn has numerous bare spots, you may need to rake a thin layer of soil over them to cover the seeds.

If you’re considering spreading compost, do so before spreading the seeds. Applying compost first helps not to bury the seeds too deep. Once you add the seeds, rake them to ensure the compost slightly covers them.

You might also want to purchase coverings that shade the soil and minimize evaporation. Wheat straw is perhaps the most affordable option. It’s also easy to use—spread a thin layer over your lawn to cover the soil. Consider removing the straw once the grass starts growing, especially if you applied a thick layer.

It’s best to hold off on mowing until the seeds germinate and grow to at least two inches. Germination often takes two to three weeks, depending on the grass type. If you mow before the seeds germinate, it may displace loose seeds.

Apply a Starter Fertilizer

You might want to apply a starter fertilizer before or immediately after spreading the grass seed. A starter fertilizer is crucial if soil test results show that your soil is deficient in Phosphorous (P), as these fertilizers are often rich in phosphorous.

It’s worth noting that adding phosphorous may also encourage weed growth. However, you won’t have to worry about the weeds once you have a dense turf, something starter fertilizer will help you achieve.


If you follow this guide diligently, you’ll successfully overseed your lawn. For the best results in overseeding a lawn, it’s advisable to work with professionals Like Yard Smart.

Yard Smart is a renowned leader in residential and commercial lawn care. For all your overseeding and lawn care needs, call Yard Smart at (647) 696-6168 to request your free estimate.

Matt Higgons

Matt Higgons

It’s been over 40 years since Matt Higgons started his first lawn mowing gig with his closest friend in high school. He used that money to pay for a business degree at St. Lawrence College in Kingston, Ontario and had big dreams of starting his own company. He never realized that the very business he would dedicate his life to, was the same one that helped him pay for that education.

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