# Celsius - How fast does it work?



## bwright (Sep 6, 2018)

How long after an application of celsius do you typically start to see signs of stress in weeds? I applied at the high rate 3 days ago, and nothing seems to be sad. I was expecting something very quick, like a roundupo quick kill.


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## FlaDave (Jul 10, 2018)

Usually about a week or 2. It will look like nothing is happening at first and then all of a sudden the weeds are gone.


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## BentleyCooper (Jun 15, 2020)

Thanks for posting this. answered my question as well. I put some down a few days ago and haven't noticed anything, although I don't even know if I'm using the right product for the weeds I have. I guess time will tell.


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## Mightyquinn (Jan 31, 2017)

The one thing you can notice is that the weeds stops growing. I think it's more noticeable is reel mowed turf. If you mow a day or two after applying it you should notice that the weeds are less noticeable since they aren't growing.


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## A3M0N (Mar 17, 2021)

I just used Celsius for the first time about two weeks ago in my backyard, and one week ago in the front. The front was definitely worse off, but like Mightyquinn said, the weeds have hardly grown at all since I mowed on Friday! Things are starting to yellow and brown, so I really started seeing results at maybe a week and a half.


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## JayGo (Jun 13, 2019)

Good question and good to get a real-world timeline from folks that have used it.
This is from the label:

SYMPTOMS
Weed growth ceases within hours after application of Celsius WG Herbicide. Symptoms progress from yellowing or reddening/purpling to necrosis, resulting in control of weeds within 1-4 weeks after application, depending on the sensitivity of the weed and environmental conditions. Weed control is more rapid when soil temperatures are above 65 degrees, when soil moisture is adequate for weed growth, and when weeds are not under environmental stress (e.g. drought).


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## NWS (May 26, 2021)

For me it has been about 10-14 days is when I see noticeable damage to the weeds. Usually spraying when it is hot. They do stop growing right away and then the abnormal growth starts at a week later (which is part of the kill method).


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## CenlaLowell (Apr 21, 2017)

Two to three weeks from my experience


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## Redtwin (Feb 9, 2019)

Celsius can be very slow to act but it is very thorough in my experience. Like @FlaDave said, it will look like it is not working at all and then all of a sudden they are all desiccated or gone. A surfactant might speed things up but I wouldn't do that in the warmer weather since it could damage the good stuff. The label covers that.


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## leefjl63 (Dec 23, 2020)

Two to three weeks as well. One day you go to cut and then notice all the weeds are gone.


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## JayGo (Jun 13, 2019)

@Redtwin, interesting point you make there about maybe NOT using a surfactant if it's too hot. I'm not finding that tip on the label, but I hear what you're saying. Makes sense.


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## southernbuckeye (Sep 29, 2019)

In my experience it's slow to work. I use it a lot when sprigging as you end up providing ideal conditions for weeds while you're trying to promote your Bermuda spreading. As others have said it will stop growth quickly but I often end up "helping" matters along by pulling up the decaying weeds to make space for the Bermuda to fill in faster. They're a lot easier to pull up then when they're alive and it can take weeks for them to fully fade away (in large open spots their carcasses will linger/block space as well).

Long story short: it's going to take time for them to go away completely but they will eventually. If you're in a hurry to fill in the spot, don't wait.


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## MrTophatJones (Apr 1, 2019)

@JayGo It's the first line on page 3 of the label. "Do not use a spray adjuvant at temperatures above 90 degrees."


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## JayGo (Jun 13, 2019)

@MrTophatJones, man, I could not find it. Finally found that line you mentioned on the label on the Bayer site. The domyown Celsius label doesn't seem to have it. I'll definitely be reading the label on the bottle today.
Thanks, man.


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## Woffski (Apr 26, 2020)

Depends on the weed you are targeting, but agree that 2-3 weeks is about right.


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## TampaBayFL (Jul 24, 2020)

It is so slow that youll think its not working....then when youve given up and thought you wasted your time and money.....youll notice the weeds are gone &#128522;

That said, certain tough ones like Doveweed may need to be treated over and over. I've killed a bunch off in my neighbors yard (usually takes 2 apps at high rate), but new ones in the same areas have still been coming back.


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## killacam (May 4, 2017)

Can I mix sedgehammer with Celsius no problem?


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## Mightyquinn (Jan 31, 2017)

killacam said:


> Can I mix sedgehammer with Celsius no problem?


Shouldn't be an issue as I have mixed it with Certainty with no problem.


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## JayGo (Jun 13, 2019)

@killacam, I just used those two together. I didn't have any problems.


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## killacam (May 4, 2017)

JayGo said:


> @killacam, I just used those two together. I didn't have any problems.





Mightyquinn said:


> killacam said:
> 
> 
> > Can I mix sedgehammer with Celsius no problem?
> ...


Great, thanks!


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## DFW245 (Jul 23, 2021)

southernbuckeye said:


> (in large open spots their carcasses will linger/block space as well).


THIS. I believe this is my problem after using Celsius, or any other weed killer ive used. I have HUGE dead spots where there is no Bermuda. Just carcasses of crabgrass that stretch out about almost 2 ft long. So you're saying I have to go in and manually remove these 'dead bodies' in order for grass to spread there? Because right now it just looks like a bunch of fungus patches where the old weeds are.


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## southernbuckeye (Sep 29, 2019)

Depends on the size but generally the larger the more likely I am to pull them. A pancake size dead weed isn't going to dust in a couple of weeks.


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## Hoghead22 (Jul 1, 2021)

So as someone posted should I dig up these "carcass" spots?? This was a spot spray after a blanket spray with Celsius and certainty.





A Celsius and Certainty blanket job before and after. This is a month between the application.


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## Redtwin (Feb 9, 2019)

JayGo said:


> @MrTophatJones, man, I could not find it. Finally found that line you mentioned on the label on the Bayer site. The domyown Celsius label doesn't seem to have it. I'll definitely be reading the label on the bottle today.
> Thanks, man.


Hmmm... I can't find it now. I'm pretty sure I have read that on the label at one time. Anyway, you can use a surfactant as long as you are OK with a little discoloring. It'll go away after a couple of mows.


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## JayGo (Jun 13, 2019)

For anyone still curious on how long it takes to see Celsius working...

This 4 days after spraying a mix of Celsius and Sedgehammer with a NIS on my neighbor's lawn. I'm impressed. I didn't expect to see results this soon.


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