Should I Cut Weeds Before Spraying?

By Mike

April 10, 2021

Having a lush and healthy yard is the perfect way to add curb appeal to your home. Throughout the year, a lush green lawn takes a good amount of work, so knowing how to combat common problems is important. 

No, post-emergent weed killer works by penetrating the leaves and stem of the plant and then carrying the weed killer down into the roots. It is often recommended to leave the plants as they are so the weed spray can work effectively. Waiting to mow your yard until after the weeds have died back is imperative to get rid of the weeds for good. 

In this article, we will break down how herbicide works in your yard and how to use it effectively. We will narrow down if you should cut weeds before spraying herbicide, as well as just how long to wait before mowing. 

Should I Cut Weeds Before Spraying 

Cutting weeds before spraying may render the weed killer ineffective and cause you to have to reapply more later. Many times mowing over the tops of weeds may look better initially, but weeds will come back in no time. If there are weeds that have already sprouted to seed, once you mow them, you simply disperse the seeds throughout your yard. 

Mowing directly after applying herbicide will waste any of the products you used on the leaves.

Weedkiller works by first starting in the leaves and then working down until it gets to the roots. Allowing the herbicide to do its job fully will minimize the odds of more and more weeds taking over your yard. 

It is often recommended to wait a few days before you see the weeds start to die back before mowing. Mowing a few days after you apply herbicide will allow the weed killer to get deep enough to kill off the weed in its entirety. 

There are a few other concerns you should be aware of after applying weed killer. It is important to also hold off on watering your yard, so the herbicide isn’t washed off right after it is applied. 

You should also wait to walk on the sprayed area until after it is mowed. Walking across freshly sprayed weeds will simply remove some of the product and have you tracking it elsewhere. 

Roundup Concentrate Extended Control Weed & Grass Killer Plus Weed Preventer II

Is It Bad to Mow Over Weeds

It is not necessarily bad to mow over weeds, but doing so will not fix your weed issue. In order to keep weeds at bay, the most important thing you can do is to keep your yard lush and full. After that, you should monitor your yard for any weeds and get rid of them before they take over. 

Mowing over weeds may cut back the top of the weed for a while, which will technically make your yard look better but won’t fix your issue. Oftentimes if you cut the weed back, it will continue to grow back until you get rid of the roots. 

Does Mowing Over Weeds Spread Them

Mowing over weeds can easily spread them from one place to another because the weeds get caught in the mower blade, and as you mow, they are dispersed. When you mow over weeds, it will often send them all over your yard, which will increase your weed problem. That is why it is important for the weeds to die back fully. 

Also, oftentimes mowing your yard doesn’t actually kill the weeds. It just cuts them back. Even after the tops have been cut off, they will just grow back.

Post-emergent weed killers should be applied to truly combat your weeds, especially if they have begun to take over your yard. Post-emergent weed killers are simply played on the leaves of the plant, and they go down into the root to kill off the weed for good. 

Ortho WeedClear Lawn Weed Killer Ready to Spray - Weed Killer for Lawns, Crabgrass Killer, Also Kills Chickweed, Dandelion, Clover & More, Fast Acting Weed Killer Spray, Kills to the Root, 32 oz.

How Long After Spraying Weeds Can I Mow

Typically, the length of time it will take weeds to die back will vary on the type of weed you are trying to get rid of. The most sure-fire way to know if the weeds are dead or dying back is to look for brown where the weeds were. This temporary discoloration will allow you to spot where the weeds have died back and allow you to proceed with mowing. 

Most often, you can mow after a few days of applying weed killer, but you should also check your yard specifically. One thing to keep in mind is the temperature outside will affect the ability of your herbicide to work fully. If you spray when it is over the temperature of 85F or on an incredibly windy day, you will have to continue to reapply the herbicide. 

Another thing to keep in mind is that you should never apply herbicide to a lawn that is already struggling. Adding herbicides to an already stressed yard can cause a lot of damage and not truly help in any way. Letting your yard grow stronger before applying herbicide will ensure your yard will grow stronger while giving you a perfect time to kill off weeds. 

The most optimal time to spray weed killer is in weather below 85F, no wind, and your lawn is overall healthy. Ensuring the optimal environment is in place will increase the likelihood of your weed killer working correctly. 

How to Keep Your Yard Healthy After Killing Off Weeds

After you have taken the time to spray weed killer on all of the weeds throughout your yard and letting them die back, you need to refocus your efforts onto maintaining a healthy yard. When you have a strong, healthy yard, you reduce the chance for weeds to find a space to grow and find sunlight and water.


The fuller your yard is, there won’t be room for weeds to grow strong and take over your yard. One thing you can do to keep your yard healthy is to mow your yard regularly. Mowing your yard regularly will allow your yard to continue to grow stronger and stronger. 


Another step you can take is to water your lawn enough to make sure it has all it needs to survive, especially during the hot summer months. Caring for your yard throughout the year will minimize the likelihood of weeds and have your yard looking stunning. 

Conclusion

Weeds in your yard can be an absolute nuisance and add an eyesore to your outdoor space. There are a variety of ways to get rid of weeds, but only some that are truly effective in combating weeds completely. Post-emergent weed killers are a game-changer when it comes to getting rid of the weeds that have taken over your yard. 

After working for months to create a perfectly manicured yard, only to find a few weeds that have popped up in your yard can be awful. Thankfully there are ways to get rid of weeds in your yard effectively. Post-emergent weed killers work by distributing herbicide to the leaves that work down into the roots. 

Once you apply herbicide, you should absolutely wait to mow as well as walk on your yard until you begin to see the weeds have died back. Waiting to mow your yard after spraying it will create a healthy-looking yard in no time. 

About the author

Hi I'm Mike! I'm the owner, writer, and sometimes editor of Foundedproject.com. Being a new homeowner can be a little daunting, which is why I created this blog. I write about problems that a new home owner might run into. 

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