Weed and Feed Killed My Grass – Why & What To Do

Nothing is worse than your lawn, the pride of your home, turning from lush and green to patchy and brown. So if you’ve recently applied Weed and Feed to your lawn, you may wonder why it’s now looking worse than ever. Besides, it’s supposed to have the opposite effect! So why does this happen, what can you do, and can your grass be restored? Well, here is everything you are going to want to know, consider and do!

So why did Weed and Feed kill my grass? Weed and Feed likely killed your grass because it was used incorrectly, whether that be by using too much, dispensing it unevenly, using it during suboptimal weather conditions, or being used on grass that is not in a sufficient state to receive treatment.  

Unfortunately, it’s quite common for Weed and Feed to kill grass, so on the bright side, you’re not alone! 

Whilst the popular product is designed to kill weeds while simultaneously providing the lawn with the nourishment it needs to stay lush and healthy, if it’s not used correctly, it can have the opposite effect – killing the grass instead of the weeds. 

Below, I’ve explored each potential cause further, as well as how you can prevent this from happening again and tips on how to revive your grass.

Read on for more information!

Why Did Weed and Feed Kill Your Grass?


Whilst Weed and Feed certainly contains the essential nutrients that your grass needs to flourish, too much exposure to these nutrients, namely nitrogen and phosphorus can be very detrimental.

Essentially, the soil becomes increasingly acidic, and your grass and its root system weaken.

As a result, your lawn will suffer from a case of fertilizer burn and will make it known by the emergence of yellow and brown dry patches across, if not all, over it. 

Additionally, it’s worth noting that over-application doesn’t solely relate to the amount of fertilizer applied during a single session.

Rather, you’ll see the same effects crop up even if you use the correct amount of Weed and Feed but apply it too often. 

An Even Technique 

Similarly, it’s crucial to apply fertilizer to your lawn as evenly as you possibly can.

Reason being applying too much of it to particular patches will over-fertilize those patches alone.

Thus, specific spots of your lawn will suffer from fertilizer burn, whilst the areas that weren’t privy to sufficient treatment will remain under-nourished. 

For peace of mind, some gardeners, particularly those with gardens on the sizable end of the spectrum, choose to use a spreader to ensure even fertilization.

Spreaders are reliable and efficient, but of course, whether you lease one or buy one outright, there’s no debating that they come at a cost. 

Time of Application 

You may have nailed the frequency of fertilizing, but it’s equally pertinent that you choose when you apply your Weed and Feed wisely too.

Avoid applying it during times of intense heat or dryness, as well as when it’s too wet.

Essentially, the less extreme the weather, the better! Generally speaking, this means avoiding Summer and Winter and, instead, opting to fertilize during Spring and even Autumn if the weather permits it. 

Lawn Condition 

Finally, it’s worth noting that before applying fertilizer, your grass should be in a decent state of health.

It’s easy to argue that it’s the fertilizer’s job to bring the grass to a place of good health, but the truth is, if your grass is too dry, discolored, thin, or even dead, the fertilizer is likely to do more harm than good for the reason that it simply won’t have the foundation that it requires to work effectively.

Your already struggling grass will find it difficult to absorb the Weed and Feed, which will, in turn, sit atop the grass and burn it. 

Can Grass Grow Back Once Killed by Weed and Feed?

Fortunately, it’s very much possible for your grass to grow back once killed by Weed and Feed. 

Admittedly, the process can be a lengthy one, and there are several best practices that you’ll need to undertake along the way, such as those mentioned below.

However, the results will undoubtedly be worth the time and effort that you put in, so hang in there!  

How To Restore Grass Killed by Weed and Feed

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

Soil Testing 

Testing your soil is worth doing even when your grass is in good condition.

It’s a fairly straightforward manual check that will tell you exactly what the state of your soil is.

You’ll learn about its nutrient and pH levels and will subsequently be well-positioned to determine the best course of lawn care action to take moving forward. 


Aerating your soil is the process of punching holes into it and is most commonly done using a spike or plug aerator or even a rake.

The purpose of lawn aeration is to create room for air, water, and all-important nutrients to reach the soil rather than getting stuck within the otherwise compact terrain.

The improved drainage and extra nutrition will allow your soil to thrive, which in turn will only benefit the grass that sits on top of it. 


Fertilizer burn can be brutally drying for your grass, and in such cases, you’ll need to water it.

This is best done once you’ve aerated your grass, at which point you can be certain that the water will reach its roots, where it will be the most effective. 

Nonetheless, it’s important that you refrain from overwatering your lawn.

If you do, you run the risk of flooding the root system and causing it to rot. 


Overseeding, or reseeding, is the process of planting new seeds across your existing grass to manually encourage new growth.

Within a few weeks or, perhaps more realistically, months, you’ll see the new grass take over your lawn at the expense of the dead patches of grass.

Say hello to a much thicker, greener, and all-around more appealing lawn! 

Healthy Lawn Maintenance 

Alongside the above interventions, it’s imperative that you maintain a consistent lawn maintenance schedule.

This means watering and fertilizing your grass to nourish and keep it well-hydrated, as well as aerating it from time to time too.

You’ll also need to be on top of weeds. Weeds are nothing but competition for grass, and they’re pretty dominant too.

If you don’t remove them, whether you opt for a herbicide or to do so by hand, they pose a significant threat to the overall health of your lawn.

Last but not least, lawn-mowing!

As well as keeping your grass looking manicured and consistent, mowing your lawn can help to remove weeds and promote healthy new grass growth. 

How To Use Weed and Feed More Effectively In The Future

When it comes to lawn care, Weed and Feed can be a very handy product to have on hand.

However, whether or not you’ll get the results you want is contingent on how you go about using it – technique is everything!

Use Proper Proportions

First and foremost, overapplying it, whether disproportionately or too frequently, is a classic and much too common cause of fertilizer burn.

Instead, you can’t go wrong by adhering to the proportions and frequency outlined on the packaging of the product. 

Apply During Spring & Autumn

Second, remember to only apply it during Spring and Autumn, and never when your grass is in a dormant state.

Weed and Feed’s effectiveness is incompatible with the harsh conditions that we tend to see during Summer and Winter, and it’s equally of no use to apply it at a time when your grass is pretty much asleep and both unable and unwilling to absorb it. 

Maintain Lawn Health

Finally, stay on top of the health of your lawn by testing your soil and actioning a consistent care routine for it.

This way, you can be certain that you’re doing all that you can for both your grass and your soil. 

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