How To Overseed a Lawn

You may have heard of the process of overseeding along, but what exactly does that mean? Today, let’s talk about the quick and easy steps that you can do in your yard to improve the overall look of things with overseeding.

What is Overseeding?

So, overseeding adds new grassy to an existing yard without removing the grass that was there; this can do many things to improve the varieties of grass that we have in there and sometimes can help you change grass type over time.

So if you live a little bit farther south, you can start this process just a little bit later into the fall. For instance, in September, right in the middle of Iowa here in the Midwest, would be a great time to start. And if you’re farther north, you want to really get this process going soon, or choose a grass type that will be a little bit quicker to grow in.

Step 1. Mowing

The first part of this process that we’re going to do is cut our grass slightly lower. Now, what does a little bit lowered mean? Well, for most people, if you’ve been trying to take care of your lawn through the summer, a lot of times, you’re leaving at a little bit higher heights. And if not, then right now, it might be a little lower already. And it might be a little brown, and it might look a little tough from summer; it just depends on your conditions.

Now, this is going to make it look kind of rough for a little while; that’s okay, do not worry about it; it will bounce back, then you’ll be wonderful. And that stress that is caused by cutting it a little bit lower here, this one time will not be an issue.

Step 2. Check the Problem Places On Your Yard

The next step in our process is to check the lawn for either thatch buildup or a lot of dead grass that happened after summertime. As I mentioned, you might have had summer stress going on, you might have had some areas that looked a little bit brown, or you got a little bit of fungus that happened during the summertime. So depending on what your grass looks like, if you feel like you need to thin it out a little bit, then we’re talking about the dethatching process.

Now, if you actually have a build-up of that, you’ll want to go out into your yard, check down by the soil layer. And if you find a spongy layer of brown and dead organic material there and you find more of a half-inch build up there, then you’re probably going to want to do this dethatching process; this dethatching process can be done here with a tool that you can buy on your own, it can be done with a rake manually, which is some pretty tough work, I will say. So keep that in mind.

You could also go to a rental place and get a dethatching machine and come in and remove a lot of that dead material, a lot of that batch material, and it’s going to open up your yard have it ready for the new seed.

Step 3. Aeration

Now the next process is technically isn’t essential to doing overseeding. But I found that core aeration can really help the process quickly. Core aeration is removing some plugs of soil, putting them up on top of the surface, letting them break down; that’ll give us a little bit of top dressing on the yard as well. But it also opens up some holes to give us some air, water, and nutrients to penetrate down into the grass’s root zone. And so that’s the whole point of core aeration.

But we can add it to our overseeding process here if we would also like to give us a little bit better seedbed, some area there for the seed to grab onto some soil up on top of the surface. And that’s the process of what you can do here with core aeration and overseeding. Together. How do you know if you need to correct it right? Well, specifically, if you go out into your yard, and you take a screwdriver with you, and you try to put it down into the ground, if you can easily put it down into the ground, then maybe this step isn’t essential for you right now.

But if you’re having trouble even putting it down into your soil at all, then I would probably recommend doing the core aeration process. Now, of course, aeration can be done yourself, go to a rental store, maybe a Home Depot, and pick up a machine. And if you’ve never done this before, just a bit of a warning, it is a workout. But I can do it, and I’ve done it many times. So I know you can do it as well. Otherwise, you can hire out of this process. There are many people I’m sure in your area about to offer this in the fall time. So check around make some phone calls if you’d like to have it hired out.

Step 4. Seeding New Grass

Now it has come to the time of our current seeding. We’re going to add our seed right over the top of the existing grass. As I said, overseeding is just adding new seeds to your existing lawn. If you’ve done that core aeration process and the dethatching, or even if you haven’t done core aeration and you can see down to the soil a little bit, you’re going to be fine there; we’re typically going to add RC with some spreader helps to make sure things are done evenly, also, on the bag of seed that you buy.

Typically it is going to have an overseeding rate on there compared to a new lawn rate. So pay attention to the rates. If you keep it fairly low, you’re not dumping piles of seed on there with your spreader. You’re probably going to be okay, but I really recommend measuring it out if you can; it’s the best way to know exactly how much you’re putting on there.

So grass seed and grassy types for cool-season lawns can get into a little bit of a big conversation here. But I will let you know that I started out using perennial ryegrass in my yard, two to three years of overseeding. And it had great results, but you have to understand a little bit of the downsides of ryegrass in a warmer climate; it can really suffer during the summertime it doesn’t really like the hot temperatures. So if you’re a little bit farther south, I would probably recommend going with tall fescue, tall fescue is going to give you the option of a little bit more summer drought tolerance, and it can withstand the heat a little bit more than has a great look to it as well.

Doyle Mathews Lawn Expert

Pro Tip: So if you're thinking about something else, you're in a little bit southern region that you have a cool-season lawn, I would think about fescue. So if you're right in the middle of the USA, you can choose some ryegrass. Most people probably are going to do Kentucky Bluegrass or tall fescue. And if you have some shaded areas look for a shade mix as well. It's probably going to have some fine fescues in there.

Now, if you’re up farther north in some of those northern sections, then Kentucky Bluegrass will do fantastic, perennial rye will do a little bit better since you’re not getting as much heat and depending on the varieties of perennial ryegrass that you choose. Sometimes it also has a little bit of difficulty surviving frigid winters. So keep that in mind as well. But if you want something quick to grow in perennial ryegrass and tall fescue will be the fastest ones. And bluegrass will take much longer to kind of come in and get itself fully established. But once bluegrass is there and into your next season’s coming up, if you’re taking care of everything very well, that Blue Grass is going to be a great grass for you and will last a long time it fixes itself, repairs holes, kind of by spreading, it’s a great grass.

Step 5. Fertilizer for Overseeding – What You Should Know

Now you got your seed down, and you want to know what to do about fertilizer. So a starter fertilizer is a good option when you’re growing in a new seed because it contains more phosphorus, which will give us some better root growth and give that grass seed a little bit more of a boost there to kind of get itself established.

There are different starter fertilizers on the market; one of them actually has a weed preventer made by scouts. So if you’re actually looking to prevent some weeds at the time of seeding, that is a product you can use; otherwise, any of the starter fertilizers you get at a store or wherever you buy them is going to be totally fine.

Doyle Mathews Lawn Expert

Pro Tip: A little tip that I found in my yard over time is that I don't typically add the starter fertilizer right at seeding. Of course, we don't want a lot of traffic on the yard after we seed. But before that new seed comes up, probably three to five days or so, it just depends. I will then add my starter fertilizer at that time, just so that I don't give that existing grass a huge boost of growth right away. Because we want that grass to slow itself down a little bit while the new grass has a chance to come up.

Step 6. Watering

So three to five days, something like that, it’s about the timeframe that I would add the starter fertilizer, just so that we’re not giving that existing lawn quite as much of an initial boost. Now one of the most important steps with any seeding project is watering. So once we get that seed down, we have to keep it wet and keep it from drying out. But this doesn’t mean putting so much water on the yard that there are puddles everywhere either. It’s a balancing act. So you need to keep the seed wet without drying out, but not go overboard.

Usually, this is a much easier process with an existing lawn because you have some existing grass to hold in some moisture. Once that seed falls to the existing grass’s root zone, it will also hold some moisture there a little bit better. So typically, probably two to three times a day with overseeding. Probably about mid-morning, maybe 11 am or something like that. And maybe about mid-afternoon, three o’clock is a good time to get some watering on there. And again, we need to get water on heavy enough to where we’re going to get that seed wet, but not so heavy that we will actually drown the seed, so probably 5 to 10 minutes per watering.

It all depends on how much sun you’re getting your location, how much when the weather; there are so many factors there, but that’s a general rule of thumb. Setting up your own sprinklers is totally fine, which is what I’ve done in the past; if you have an irrigation system makes things a lot easier.

Step 7. Keep Mowing Frequently

Whatever machine you use, make sure your blades are sharp. And if you’re using a rotary mower, try to be as gentle as you can on it and try to get on the lawn, get off the lawn as quickly as possible, get a good clean cut on there. And then, through the fall time, keep up your mowing frequently. And I know this is something that people probably don’t think is extremely important.

But if you can get out there every three days during the fall, that would be absolutely amazing to continually cut this get it to thicken up a little bit; that’s going to help you in the next season as well if you can keep that mowing up. Keep your machine running at a high level, keep your blade sharp; this alone is going to make a big difference in your yard this fall. It is probably about four weeks after the process of initially seeding. That’s when I’d probably add another dose of starter fertilizer or really any fertilizer at that time, and it doesn’t really have to be starter fertilizer. But that’s a good timeframe after you’ve probably mowed once or twice something around there that will work well.

Final Words About Overseeding

And what about weeds. So when our grasses coming in, we have just to let it be as it is. Now there might be some existing weeds that come in. Don’t worry about these too much at this time because our whole goal is that by adding this new seed by mowing properly by doing all these things, we’re going to choke out those weeds naturally. And once your lawn gets thick enough, it will actually choke out those weeds, and they will not be able to grow. So don’t worry about it too much at these initial stages.

After you’ve mowed probably three to four times, usually most bottles will say at least three to four times, then you can come in and kind of target some of those weeds that might have come up. So keep that in mind for three to four mows. After you’ve done that, you can come in and spray a little bit. I usually use a regular we’d be gone product, something over the counter, and target the weeds I’m finding in my yard. That is the process of overseeing a lawn, and it might sound a little bit daunting at first. But I promise you if you follow these steps, you will have a much-improved yard this fall and coming into the next seasons as well.