Roundup Killed My Grass – Why & What To Do

Roundup is a tried and true product that many gardeners rely on repeatedly to kill weeds. Hence, it’s only natural that you’d assume it would work wonders for your garden too. But of course, there’s a catch! Roundup may be more than capable of killing your weeds, but it may just kill your grass too! 

Finding yourself left with dry and discolored grass is probably the last thing you expected, so it’s understandable that you’re puzzled, irritated, and of course, looking for answers. I’m here to provide them today.

So why did Roundup kill my grass? Roundup can kill grass if it is applied inaccurately, as a result of the weather conditions/time of year at the time of application, or due to the state of the lawn at the time in which it is applied.

Below, I’ve explained why Roundup may have killed your grass, as well as how to prevent it from happening again in the future, and even how to restore your grass back to its former glory. 

Why Did Roundup Kill Your Grass?

Incorrect Application 

First and foremost, it’s important to be aware that one of the most common Roundup weed-killing products on the market is actually a non-selective herbicide.

This means that it threatens to harm any and all plant life that it comes into contact with, as opposed to weeds alone.

Hence, precision during its application is an absolute must, but admittedly, it’s tricky to achieve when you’re spraying it across your entire lawn.

So, if you notice that Roundup killed your grass, as an initial step, be sure to check the bottle you used – perhaps it was the wrong product! 

Fortunately, there is a Roundup product that is made especially for lawns.

However, whilst it’s much less likely to, it is still very much capable of killing your grass.

Often, this is due to the technique adopted whilst applying it. Namely, the proportions used.

For instance, if you apply too much of it, your grass will struggle to properly absorb it, in turn leaving it sitting on top of your lawn as opposed to getting to work on those unwanted weeds.

As a result, your grass will suffer from a case of herbicide burn and turn dry and a yellowish-brown color in the process. 

Time of Application 

When it comes to applying Roundup, there’s a pretty specific annual schedule that you ought to stick to.

The first rule of thumb is to only apply the solution when the weather is both calm and dry.

You should also avoid rainy conditions for at least 24 hours after its application to ensure that it doesn’t wash away before it has a chance to take effect.

Thus, the best time of year to apply it tends to be during the Spring and early Summer months.

According to the team at Roundup themselves, this is especially true if you’re dealing with weeds such as dandelions, foxtail, and crabgrass.

Others, such as chickweed and henbit, are best treated in the slightly cooler conditions that Autumn brings. 

Lawn Health 

Finally, you should only apply Roundup to established grass.

This means refraining from applying it directly after aerating your lawn and, more generally, avoiding applying it if your lawn happens to be in a state of suboptimal health.

Reason being, if your grass is already dry or weak, it’s most likely not in the condition that it needs to be to absorb the Roundup well, let alone to remain resilient when it comes into contact with it.

Once again, the Roundup will merely sit atop the grass and burn it. 

Can Grass Grow Back Once Killed by Roundup?

Fortunately, no matter the degree of damage caused by Roundup, whether you used the wrong product or not, grass is renowned for its durability, and in most cases, there’s no reason why you shouldn’t be able to revive it.

However, your grass won’t ‘bounce back.’

Rather, there are several steps that you’ll need to take to nurture it back to good health.

The process may be time and energy-consuming, but try to remember that it’s only for a limited period of time, and it will pay off in the long run! 

How to Restore Grass Killed by Roundup

Follow the below tips, and you’ll revive your grass in no time! 

Test Your Soil 

Testing your soil, which is fairly straightforward to do, will help you to make an educated guess as to what exactly caused your grass to die, as well as inform you on the current state of it.

Now, equipped with information on its nutrient levels and much more, you’ll be able to take the curated measures necessary to revive it, as opposed to undertaking more general and less effective endeavors. 


Next, I highly recommend that you take the time to aerate your grass.

This is the process of using an aerator, or even a rake, to poke holes into your lawn and the soil beneath it to create more room for nutrients, water, and air, to travel to the root system.

By ensuring that the essentials are right where they need to be, you’ll encourage your grass to grow as healthily and efficiently as it can.

The Fundamentals 

If your grass isn’t doing too well, it will definitely benefit from water and fertilizer alike (once you’ve aerated it, of course)!

The water will provide it with much-needed moisture to combat its dry nature, as well as enable it to go through the all-important photosynthesis.

Meanwhile, the fertilizer will provide it with an essential nutritional boost. 

The result of both of these measures can only be improved health! However, this is only true if you have tested your soil and know exactly which nutrients it’s deficient in.

Then, you’ll be well-placed to apply a fertilizer made up of the nutrients it actually needs rather than counterproductively feeding it what it already has. 


It’s also worth considering reseeding, or rather, overseeding, your lawn.

New grass will grow, and despite its young age, it will be much stronger and healthier than the old dead grass.

Subsequently, it will dominate your lawn, and in a couple of months’ time, your grass will possibly be even greener than it was before the whole Roundup escapade! 

Lawn Care Routine

Finally, if you don’t already have a consistent lawn care routine, now is the time to establish one.

You should be watering and fertilizing your grass frequently, as well as mowing it and staying on top of all things weed and pest removal.

This routine is important both when your grass is happy and healthy and even more so when it’s dead.

Your efforts will ensure that your healthy grass is able to thrive, or if it’s dead, that it will simply survive!

How To Use Roundup More Effectively In The Future

Roundup is a fantastic product and is rife with benefits. When used properly, it can do your garden a world of good! Really, its success boils down to your technique.

For ease, here’s a quick summary of the practices for you to keep in mind as you strive to remove those pesky weeds:

Use The Right Roundup Product

First, make sure you’re using the right product.

It may seem obvious, but there are a few Roundup products on the market, and as mentioned above, you’ll want to use the one that is fit to be used on grass.  

Stick To Suggested Quantities

Next, when you apply Roundup, stick to the recommended proportions and frequencies as recommended by the company itself.

This will prevent you from over-applying it and causing herbicide burn. 

Apply During Spring/Autumn

Additionally, be sure to use it at the right time in line with the weeds you’re working with.

For instance, dandelions should be tackled during Spring rather than Autumn.

By sticking to Roundup’s guidance, you’ll use the product effectively rather than wasting it and harming your grass in the process.

Implement A Lawn Care Routine

Finally, try to keep up a productive lawn care routine.

This will keep your lawn in good health around the clock, which is both generally beneficial, and will also ensure that you can use Roundup whenever the need strikes.

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