How to Overseed Your Lawn

All lawns need their fair share of attention and care in order to stay as green and healthy as possible.  Over time, your lawn can become worn down from use and the elements.  Your grass may start to thin out and become weaker than it was when you first seeded your lawn.  Luckily, there is an easy solution when your lawn needs to be refreshed.  If done correctly, overseeding your lawn will restore your grass to its thick, green blades that will endure against wear and tear while resisting weed growth.

overseeding lawn

Overseeding vs. Reseeding a Lawn

It is important to know the difference between overseeding and reseeding a lawn.  Reseeding means removing all the existing grass in your lawn and starting with a blank canvas.  This process is pretty time-consuming and expensive, and for that reason you shouldn’t reseed your lawn when it isn’t necessary.  If you wish to treat small thin patches in your yard or make your lawn grass look thicker overall, overseeding is the best solution so that you do not have to completely regrow your lawn.

Is Overseeding Worth It?

You may be considering whether or not it is worth the investment to overseed your lawn, but when your lawn becomes worn out and the grass grows thin, your yard is far more susceptible to weeds.  Another reason is that as your grass grows older, it becomes more difficult for the plant to produce new blades over time, which results in thinner grass year after year.  Overseeding your lawn will thicken the grass and not only make it look fresh but also protect it from invasive plants.

Preparing to Overseed

Before you spread the new grass seed over your existing grass, there are a couple of steps you must complete to ensure that overseeding will have the biggest impact.

Mow Your Lawn Low

Mow your lawn and cut the grass much shorter than you normally would, leaving no more than an inch or two of grass.  This way, when you lay down the new seeds, they will be as close to the soil as possible and will have a better chance of taking root. After mowing, rake the lawn to pick up any grass clippings, dead leaves or other debris laying in your yard.

Dethatch The Lawn

Dethatching is bascally removing the “thatch” layer of dead grass that is covering the soil in your lawn. This is an important step that shouldn’t be forgotten.

When you dethatch your lawn, you are giving your new grass seed a better chance to make direct contact with the soil so that it can take root. If the seed sits above the soil on top of the thatch layer, it won’t take root.

You can simply use a rake to remove the thatch from your lawn or there are also dethatching machines that are available for rent from your local home improvement store. These are also sometimes called “power rakes”.

Rent a Lawn Aerator

Aerating your lawn, like dethatching, is an important thing to do prior to overseeding.

Lawn aeration is the process of poking holes in and pulling plugs of soil out of your lawn. What this does is it allows air to circulate much better in the soil, it de-compacts the soil and it also allows your new grass seed to fall into the holes that are left behind.

Topdressing Your Lawn (Optional)

Also consider topdressing your lawn with compost, because the compost will provide an excellent bed of nutrients for the new seed.  The primary concern with your preparations should be to guarantee that your soil is as healthy as possible before overseeding and nothing will inhibit the new seeds from coming into contact with the soil.

You can also topdress your lawn after overseeding. This will cover the new seed with soil (direct soil contact with seed) and it will also make it harder for birds to eat your seed before it has a chance to grow!

Which Seed to Buy for Overseeding?

Depending on what type of grass you have in your yard, you should purchase the corresponding type of seed.  There are a variety of seeds available for cool-season and warm-season grasses of all types, so it is important to make sure you buy the right one for your lawn.

In many cases, you can buy a mix of grass seeds that incorporates some seed varieties that grow faster along with others that will germinate slower.

For example, for northern lawns, a popular grass type is Kentucky Bluegrass. You can buy Kentucky Bluegrass in it’s purest form or you can buy a mix which usually contains tall fescue. This mix gives you the beauty of Kentucky Bluegrass with the fast germination time of tall fescue so that your lawn fills in quicker while still allowing the Bluegrass to grow.

Coated Grass Seed vs. Uncoated

In recent years, grass seed companies have been producing coated grass seed. This coated seed is typically coated with a chemical that allows the seed to absorb more water vs. uncoated seed. The coated grass seed also needs less watering after overseeding than you would need with uncoated grass seed.

Coated grass seed is typically more expensive than uncoated, but we recommend going with coated seed in most cases since you will be getting much more growth (more seeds germinating and growing grass) vs. uncoated. You get what you pay for.

When to Overseed Your Lawn

For cool-season grasses and northern regions, it is best to overseed a lawn in early fall.  For warm-season grasses and southern regions, overseed in late spring or early summer. You want to make sure to overseed when the soil temperature in your area is above about 60 degrees Fahrenheit and during a rainy season. You definitely don’t want to try to grow seed in the middle of a hot summer where the soil temperature is higher and there’s less rain than spring or fall.

How to Spread the New Seed

Use a fertilizer spreader to distribute the seed throughout your yard.  Any handheld, broadcast or drop spreader will work for overseeding – choose the type of spreader based on the size and shape of your lawn for ease of use.  The amount of seed you will spread depends on how frequently you overseed your lawn.  If you overseed every year, you probably won’t need to use as much product as you will if this is your first time overseeding a patchy, thinning lawn.

Topdressing Your Lawn After Seeding

After you’ve distributed the seed, apply a light layer of soil on top of the new layer.  Do not mow your lawn until the seeds begin to grow to nearly the level of the pre-existing grass blades.  Otherwise, your mower will disturb the loose seed and it will not take hold in the soil.  Water your lawn lightly at least once a day for the next week to keep the soil as moist as possible.  Another great way to nurture the new seeds is to apply a “starter” fertilizer, or a fertilizer that is rich in phosphorus to help strong roots develop in the soil.

Water Your Lawn Regularly

Now that you’ve put in the effort to make your lawn ready and overseed, you don’t want to “forget about it” and not water your lawn. After overseeding, your main goal is keeping the seed moist.

This doesn’t mean that you have to flood the lawn with water, but it does mean that you want to turn the sprinklers on for about 15 minutes both in the morning and the late afternoon each day for about 2 weeks. It’s a small investment to make sure that you’ll have lush, thick grass in the future.

Overseeding Makes For An Impressive Lawn

If you follow the best practices for overseeding, the process should not be too difficult and will yield valuable results for your grass.  Many people do not take the time to overseed, but they wonder why their grass has grown thin and weak over the years.

Every lawn needs the proper attention and nourishment, and overseeding is a necessary step in restoring your grass to full health.  In fact, many lawn care enthusiasts make it a priority to overseed their lawn every year.  It is better to act early and overseed in order to prevent thinning grass, rather than waiting until your grass needs immediate help.