How soon after spraying weeds can I mow? (Find Out Here)

Most homeowners spread weed killer and fertilizer on their lawns during spring. Weed and feed is a combination of herbicides that kill weeds and pesticides that simultaneously help to improve the health of your lawn.

Most herbicides you use on your lawn grasses go to work quickly and halt the growth of weeds immediately, but it can take a few days to a month to completely kill all the weeds.

So how soon after spraying weeds can I mow? the answer is waiting 24-48 hours after applying a weed killer to mow. This will give the herbicide enough time to be absorbed into the roots of the weeds and kill them.

How do weed killers work?

Herbicides are used to specifically kill weeds and unwanted vegetation in your garden or crop field. Most will either destroy the weeds entirely or cause severe damage. Some weed killers are designed to eliminate specific weeds, while others can kill all weeds.


Targeted weed

Best spraying time


Palmer amaranth


2 4-D

Palmer amaranth

8 am-7 pm


Barnyard grass

12 noon and 6 pm


Palmer amaranth

12 noon

Types of weed killers

  • Systemic

Most herbicides are systemic which means they can be absorbed by any part of the plant from the leaves to the roots killing every part of the weed.

The 2 4 D is a selective weed killer that is very effective in dealing with perennial weeds.

  • Contact

This herbicide is used on living green weeds and it gets absorbed into the leaves which makes it very effective when the weed is actively growing and taking in sunlight.

This herbicide should be applied early in the morning to give it time to be absorbed by the leaves and very good at handling annual weeds.

  • Residual

This weed killer is also known as soil acting and can only be used in places like paths and patios because they poison the soil to prevent the germination of any seeds.

They can stay for months in the ground so it’s not advisable for areas you want to grow plants.

How long does it take for weed killer to work?

How long weed killers take to work will vary depending on the type of weed killer, the weeds, and the conditions you’ve applied it in.

Generally, it takes 2-4 weeks to completely get rid of all the weeds and unwanted plants in your lawn.

The first signs you’ll notice are the leaves turning yellow and wilting.

However, avoid spraying the weeds when it’s raining, the herbicide will be washed away and it won’t have any effect on the weeds.

Also, don’t spray when it’s windy, the weed killer can be blown away to other plants nearby that you don’t want to kill.


Hand pulling weeds can be both tiring and time-consuming and if your lawn has a serious weed problem, you should use a weed killer to do a better job.

However, you should give the herbicides enough time to penetrate the weeds to completely kill the weeds.

Also read

Does Boiling Water Kill Weeds

Should I Bag my Grass Clippings if I Have Weeds

Does Weed Killer Expire? (Shelflife of weed killer)


What is the proper way to apply broadleaf herbicides to the lawn?


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