People often ask if they should kill weeds before or after seeding their lawn. The answer depends on a lot of factors. Learn the lawn care timing that’s best for your lawn. Get your FREE Guide To Fall Seeding from the Lawn Care Nut featuring questions and answers about spraying weeds leading up to the seeding, you do NOT have to kill all the weeds at once and more now! Whether the grass needs spraying for weeds or seeding , it’s possible to get both issues handled by using our customized treatment plan.
Should I Kill Weeds Now or After Seeding My Lawn? Tips for Fixing Lawns in Cincinnati, Dayton, OH, or Northern KY
Timing is everything. You’ve likely heard this said many times before and can come up with a variety of ways that it applies to your life. So, you shouldn’t be surprised that it also applies to lawn care.
Amongst your timing questions, you might be wondering whether you should kill weeds before seeding or if one time of year is ultimately better than another. Should you wait?
The answer depends not only on the time of year but also on your expectations, including what you want to achieve.
Let’s look at a few important things that you should know as you ponder what’s best for your lawn.
The Best Defense Against Weeds is a Thick Healthy Turf
You’ve probably heard us say this mantra before and it’s a good time to emphasize this point again. Both your healthy grass and your weeds compete for the same water, oxygen, and nutrients. That’s why weeds thrive in bare spots and why one of the best ways to combat weeds is to thicken your lawn and choke them out.
A thick and healthy lawn is best achieved by enlisting various lawn care treatments from spring through fall and also adding a service called lawn aeration .
Lawn aeration helps relieve compaction and allows more water, oxygen, and nutrients to penetrate deep into the soil. Seeding is best performed at the same time so that the seeds can fall into the holes which were created and receive the optimal seed-to-soil contact they need to germinate and thrive.
Of course, this is where timing matters.
Lawn aeration is a service best performed in the fall when the weather is ideal for seed germination . In the fall, the air is cool but the ground is still warm, which will give grass its best chance at growth.
But if you plan to kill weeds before seeding the lawn, it might not be that simple. Trying to optimally time aeration and overseeding with weed control applications is important.
We can aerate and overseed 3 weeks after using broadleaf weed control products. That means, ideally, we want to spray weeds by mid September so that we can come back in mid October to perform aeration and overseeding. SInce it’s such an important service, it’s really not one you want to skip.
Should I Kill Weeds Now or Later?
Keeping in mind the importance and the optimal timing of lawn aeration and overseeding, you should know that the answer to the question about the best time to kill weeds is usually “now,” unless you’re reading this in the fall.
If it’s after mid September, we’re going to need to discuss your expectations and your goals as we make a decision on what’s best for your lawn.
Quite likely, you’ll benefit most from holding off from performing weed control in order to allow us to complete lawn aeration and overseeding. If you treat weeds late in the fall and skip aeration and overseeding, you’re only going to have more bare patches and more weeds creeping in. This will set you back even further than you are now.
It’s likely best to hold off on weed control for now and then get started with the right weed treatments when the timing is ideal.
A Word on a DIY Approach
In having this conversation about whether you should kill weeds before seeding, we recognize that you might be thinking about tackling this on your own. Maybe you’ve recently fired a lawn care company that wasn’t achieving the results you’re after or maybe you just feel like this is something you can handle yourself.
If that’s the case, you might even be considering DIY seeding. Perhaps you have just a few bare patches and you decide to toss down some seed to fill it in. You might even be a customer of a lawn care company but assume that you can still do some of your own seeding.
We would urge you of the importance of communicating with your lawn care company about what you’re planning to do.
We always talk to customers about not taking steps in between our visits to perform DIY lawn care services because it could do more harm than good. Even if you’re just trying to do something simple and toss down some seed and fill in a bare spot, you could actually be contributing to your weed problem. A lot of people don’t realize that the seed sold at big box stores commonly contains filler and even weed seeds. As a result, you might be filling in your bare spots with undesirable grasses.
At Oasis Turf & Tree, we use premium grass seed that is 99 percent pure so that we’re not planting more weeds in your yard.
Don’t give into temptation and take matters into your own hands. If you’re a client of Oasis Turf & Tree, trust that there is a process at work and you may just need to give it some time.
Let Time Do its Magic
It really does come down to the fact that timing is everything.
There is a “best time” to perform lawn care services to ensure that they work the way they’re supposed to but also that they don’t negatively interfere with one another. Poorly timed weed control treatments can obviously impact your new seed growth and you don’t want that to happen.
We understand that there’s a lot on the line here. You want your lawn to look its best, you may be investing in services, but you might not feel like waiting. However, it’s so important that you’re taking the proper steps in the proper timing. Sometimes it does mean having some patience and looking at the big picture.
At the end of the day, one of the best benefits of hiring a professional is handing your worries over to them instead of being burdened with them yourself. When you hire Oasis Turf & Tree, you let us handle these tasks so that you don’t have to. That means we’re applying our knowledge of optimal timing to help get you the results that you truly desire with no hassles on your end. You might have to be patient but you’ll see that it will pay off tremendously.
Want to learn more about professional lawn care services for your Cincinnati, Dayton, Ohio, or Northern Kentucky home? Request your quote, choose the lawn care program that’s right for you, and then sit back and relax as the pros help you get the lawn of your dreams!
Should I Spray For Weeds Before Seeding
Since releasing this year’s FREE Guide To Fall Seeding we have had some questions come about spraying weeds now leading up to the seeding. In and this blog post will answer those.
First off, you do NOT have to kill all the weeds. The winter is going to kill them for you and having a few here and there will not get in your way too badly. However, if you have had a big emergence of crabgrass in your lawn (where it is all you can see), you will want to try and knock that back some – mainly so it doesn’t go to seed on you.
It’s probably hard for you to tell, but this lawn here is in Munster, IN and this is 99% crabgrass.
Here is what it looks like up close:
If this is you, you will want to spray this and start knocking it down. Leaving it in there is good because it will help hold your seed in place but for sure, if your lawn is this thick with crabgrass, hose it good with quinclorac , quincept or mesotrione leading up to seeding following the recommendations below.
Note on Details:
I’m going to get highly detailed here because I respect you and your intelligence. You’re smart and therefore you can and should seek to understand these chems so you can get the proper result from using them and have no fear of them. I respect the fact that once you take the time to understand this example, you will be better at discernment of similar questions in the future and thus you will be more confident in your approach and strategy. In other words, I’m not going to talk to you like you’re dumb and just tell you what to do. Instead I’m going to teach you like a professional. I hope you are good with that.
Second, I respect the green industry and the lawn pros who make their living doing this day in and day out. When you use professional formulations of products like the ones listed here, I now view you on their level and that also means we need to stay within the bounds of the label which is the law. If you see YouTubers or social media influencers out there not following the label, including me, you should call them/me out. Everyone makes mistakes here and there, but it’s their reaction to being called out that truly shows their intent. I like to think everyone means well and is willing to admit when they are wrong.
Can I Spray Weeds and Kill Crabgrass Now if I Plan to Seed In September/Fall Time?
This is the most common question and it’s difficult to answer for all of you so I’m going to show you how to find the answer for yourself using 2 examples.
Reading The Label – Quinclorac 75DF
Key: The answer to your question is on the label. Labels of weed control products almost always tell you the wait time until seeding after application. Let’s look at two that you likely may be using.
First one is quinclorac . This is the first choice active ingredient that kills crabgrass that you may be seeing. If your lawn is covered in crabgrass like a carpet – especially through the middle or meaty part of the lawn, you will want to kill it off or at least stunt it really well before seeding.
The formulation most of you have is the “DF” which stands for “dry flowable” which means it’s small granules that you put in water to make a solution to spray. The concentration is 75% quinclorac.
Here’s the trick to reading labels fast. Find the PDF online. Make sure it is the VERY SAME product you have in hand. DoMyOwn is a great resource for this .
Once you pull up the label, hit “command F” on Mac or “control F” on PC and this opens up a search window. Type the word “Seed” in that window and it will reveal how many times that word appears in the label PDF.
Use the down arrows in that window to “scroll” through all the instances where that word appears. As I did this, I found the following very quickly.
So we can see that for certain types of seedings, this product won’t cause any harm at all but we have to scroll down to the tables 1 and 4 to get the details. Table 1 is going to tell us the grass types that are “highly” and “moderately” tolerant and table 4 will tell us the timing of the applications for ANY seeding.
This is where it sometimes gets confusing so follow along with me.
Here is Table 1
So what this is telling us is that you can use Quinclorac 75DF on established grasses listed as “highly” or “moderately” tolerant. That is really all this chart is for. It has nothing to do with seeding, hence the word “established.” But you still have to look at this chart first to find out if you should even use this product in the first place.
It’s main purpose is to tell you that you should not use this product on Bahia, Colonial Bent, Centipede or St Aug, period. Doesn’t matter if you are seeding or not, you should NOT use this product on these grass types. It also warns you about using it in or around fine fescues – they must be part of a blend if you do.
So in our case, where we are thinking about seeding the lawn, if we are planning to seed Bahia grass for example, then this product is out, 100%. No Bueno.
So if you passed the test on this part and are seeding Kentucky Bluegrass for example, then you need to next consult table 4 which is going to give you the timing of seeding both before and after.
Let’s stick with our example of Kentucky Bluegrass and you can see that it’s ok to apply quinclorac to the lawn to kill crabgrass 7 days before seeding or more. So right now, if you are let’s say 2 weeks away from seeding, you are welcome to spray away and kill that crabgrass dead. (note, this product turns crabgrass orange/red in about 6 days. But it takes much longer for the crabgrass to fully break down so likely some of it will still be there when you seed, just red and dead).
Also of note, if you have crabgrass living after or during your seed grow in, you have to wait 28 days after emergence (when you see it) before spraying. It’s important to understand what mix you are seeding in this case because if you have a tall fescue, bluegrass mixed seed , the tall fescue will emerge in about 10 days but the bluegrass won’t emerge for 18-21 days so you need to wait 28 days AFTER THE BLUEGRASS emerges before spraying quinclorac. If you really want to be safe, wait the 28 days and 1-2 mowings before applying – this adds some extra protection for the late bloomers as mowing encourages new grass to “harden off” quicker.
Reading The Label – Seeding and Tenacity – Mesotrione
( we have the generic which is cheaper FYI)I will throw this one in real quick because it’s a little different. We recommend this product for a pre-emergent application at the time of seeding. It will suppress certain weeds in your grow in. If you are new and inexperienced, DO NOT think you have to use this – your results will be ok without it. But if you do use it, people think they can just spray it anytime they want and this is not true.
You can spray it anytime you want leading up to seed day, and on seed day, but once your seeds germinate, you should NOT spray it again until the new gras has been mowed 2-4 times or 4 weeks whichever is longer.
So to be clear – you can apply this up to seeding, but once the seed germinates (4-5 days for rye, up to 21 days for bluegrass) you should NOT apply it to weeds until the new turf has been mowed 2-4 times or 4 weeks, whichever is longer. This is because baby grass is weak and can’t withstand/tolerate mesotrione .
Reading The Label – Speed Zone – Red Label
This is another weed control I have recommended heavily and they list right on the label in clear printing how long to wait until you seed. Keep in mind, this product has an 85F degree temp restriction anyway so many of you would not be using it in summer, but in case you did, here is the wait time after app before seeding:
Reading the Label – Quincept – New Farm
Ok now just as I make everything seem like it’s as simple as reading the label, NuFarm (who I love) comes in and just leaves it off their Quincept label completely . Maybe someone from NuFarm can Tweet me and let me know why y’all have left this off your label for so many years… is there a typo you have not corrected? I have read and read the label and this is all I can find – it’s all about “spraying after you seed” but nothing about “spraying before you seed.”
You can read that all you want, backward and forward and it only tells you about “after” seeding. And since I have recommended this weed control so heavily this year I feel like I need to provide an answer.
First off, when I worked for TruGreen ChemLawn, Quincept was our go-to weed control for summer and I remember that every year that right around 3 weeks before overseeding time we would get a memo telling us to cut off the Quincept use. The memo would come early but would read “stop spraying Quincept 2 weeks prior to starting your overseedings for customers.”
So that is my first clue as to the reseed window – it comes from my experience.
Next, I found a product that is similar to Quincept in that it has the same active ingredients plus one. That is Q4 Plus . It has very similar concentrations of the active ingredients within the Quincept plus one more. That product says this:
In short, if you are using Quincept, wait a minimum of 14 days after application to throw down your grass seed. I had to use some logic with this one and figured I’d share it just in case you are doing all the research and coming up empty. Now you know.
So there you go, all about reading labels for seeding – hope this has helped you and that your seeding will be successful this season!
Welcome to the official site of Allyn Hane, The Lawn Care Nut from YouTube. Here you will find my free newsletter that gives you much more than just the tip. I also carry the full line of N-Ext soil optimization products including RGS, Air8 and De-Thatch along with MicroGreen and Green Effect plus much more!
Seed First or Spray First – Which is Best?
Weed control treatments are tricky. You need the correct product applied at the right time to make it work. The first step in the process involves the assessment of your lawn. The decision to seed first or spray first depends on the result of this.
Why Skipping Spraying Won’t Work
You might think that the problem is over because the plants die off during the winter. Seeing dead weeds in your yard means that the plants have entered a new growth cycle.
Many species drop seeds that can lie dormant for years. Once the right combination of water, sunlight, and temperatures arrive, they can pop up fast. This is why you may feel like hundreds of weeds have grown overnight.
Certain weed varieties thrive during the winter. Mediterranean grass is an annual grassy type of weed that is commonly found in Arizona. Winter weeds often show up as patches of tall green grass among a sea of brown desirable grass blades that have done dormant.
If weeds are allowed to grow, they can have a devastating effect on grass. Weeds often have deeper and wider root systems that enable them to get water first. Tall weeds block sunlight from reaching shorter grass blades.
Getting control over weeds at the start of the winter and spring seasons protects desirable grass in each critical growth stage.
Analyze the Current State of the Landscaping
Lawn maintenance plans are based upon what type of plants are growing on your property along with the current season.
Lawns with minimal weeds growing may be seeded before doing a full-lawn spray. In this case, you could spot spray the few weeds that you see or hand-pull them.
After seeding, you’ll then need to wait the appropriate amount of time before arranging for pre-emergent weed spraying. While you wait to spray for weeds, this might be a good time for fertilizing or soil treatments.
If your lawn has a large number of weeds, then it might be in your best interest to tackle them first and worry about seeding later. This is especially true if you have a little time left in the primary grass sprouting season.
Post-emergent weed sprays are less likely to disrupt seed germination and grass growth. Selective sprays that target broadleaf weeds are also safer to use since they don’t affect the grass.
Using the right spray is just as critical as the timing that you use for the application. After any weed spray is used, find out when you can plant grass seed.
Certain types of weed spray allow for seeding to occur as soon as the next day. Other types may require you to wait a few weeks.
Know How to Get the Best Results From Seeding
Overseeding a lawn is often necessary to replenish grass that didn’t survive the harsh summer or winter seasons. Grass seed needs to reach the ground for it to have the best chances of sprouting. Eliminating competition from the weeds helps grass seed to have what it needs to grow.
Once the weeds die off, remove the dead plants, and consider dethatching the lawn. Then, apply the seed using the recommended application method and water thoroughly to ensure it sprouts.
Whether to spray or seed first is often as hard to figure out as the age-old chicken or the egg debate. With Arizona lawns, the answer to this question can change each year and even with each season.
Let us know about any problems that you’ve noticed over the past couple of weeks. Whether the grass needs spraying for weeds or seeding more, it’s possible to get both issues handled by using a customized treatment plan.