# Tenacity in November?



## jeffman2 (Apr 8, 2019)

Hey guys I'm in Massachusetts and have a cool season lawn. I over seated August 29 and prior to that put down tenacity. Do you recommend putting an application of tenacity down in November to keep away winter weeds?


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## Harts (May 14, 2018)

In my opinion, the timing is too late:

1) Tenacity only offers a 30 day pre-em window and doesn't do much in the way of protection over the Winter the same way Prodiamine or Dithiopyr would

2) Winter annual weeds are likely fully germinated by now. Even an application of Prodiamine or Dithiopyr would be a wasted app

You generally want to get a fall pre-em app down before your soil temps reach 70F.


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## Thejarrod (Aug 5, 2018)

In addition to Harts points above, I'll add one more. 
Tenacity can cause the good turf to turn white. this is a temporary situation, but the grass needs time to recover. I sprayed some winter weeds on 10/18. I'll be going dormant very soon and i now expect that it will be damaged until spring. it really stinks to have these patches in an otherwise healthy lawn. 
here is a pic from a couple days ago.


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## ColeLawn (Nov 11, 2020)

Harts said:


> 1) Tenacity only offers a 30 day pre-em window and doesn't do much in the way of protection over the Winter the same way Prodiamine or Dithiopyr would


Not to hijack this thread, but how early (western NYer here) would you put down Tenacity in the spring? This is a lawn that has never been properly cared for and although it has potential, it's pretty weed infested currently. So far since the beginning of October I have put down two applications of liquid Weed-b-Gone (2 weeks apart) and I just put down Milo at bag rate (Thanksgiving feed) this weekend and was going to do the same in the spring.

Next fall is top dress/over seed. Until then is preparing the lawn for that project.


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## Thejarrod (Aug 5, 2018)

I used Tenacity for the first time this year. i had grassy weeds like nimblewill and bentgrass so i gave it a shot. it was pretty effective on those weeds . But after my experience, I would urge caution against using tenacity as either a pre-emergent or a general post emergent weed killer. its a specialty chemical that has its place, but its tricky to use and is not the best option for most people. 
prodiamine (my choice) or maybe dithiopyr will be the best options for general spring pre-emergent. 
if you haven't already read it, check out the cool season lawn guide here. 
https://thelawnforum.com/viewtopic.php?f=9&t=1595


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## Harts (May 14, 2018)

ColeLawn said:


> Harts said:
> 
> 
> > 1) Tenacity only offers a 30 day pre-em window and doesn't do much in the way of protection over the Winter the same way Prodiamine or Dithiopyr would
> ...


I wouldn't recommend Tenacity as a general post-em herbicide. It is best used during a renovation. Yes, Tenacity does bleach your good grass and it does grow out, however, there are other options out there that will get the job done.

If your lawn is really bad with weeds, you might want to consider nuking it and starting over. But first thing is to identify the weeds you have. It could be that Weed B Gon is ineffective against some weeds you are seeing. A few examples would be any grassy type weed and crab grass.

If you do plan to seed next Fall, I would hesitate to put a pre-em down as it will inhibit seed germination unless you went with a 3 month rate and over seeded in late Aug to early Sept.


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## bf7 (May 11, 2020)

Thejarrod said:


> In addition to Harts points above, I'll add one more.
> Tenacity can cause the good turf to turn white. this is a temporary situation, but the grass needs time to recover. I sprayed some winter weeds on 10/18. I'll be going dormant very soon and i now expect that it will be damaged until spring. it really stinks to have these patches in an otherwise healthy lawn.
> here is a pic from a couple days ago.


If you don't mind me asking, what rate of Tenacity was this, and is this area all fescue?

I put down two rounds at 2 oz/acre, one on 10/28 and another on 11/6. My goal was to weaken my poa a going into winter. I was a little concerned about stunting the turf. But I have yet to see any bleaching on the good grass. It's definitely highlighting the poa a. I have all KBG.


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## Green (Dec 24, 2017)

I do not recommend it unless you want to kill your grass. Seriously. Been there, tried that and it worked too well. But even if you wanted to do that, you'd have had to start in early October and apply every 14 days until you reach the label rate. I had dead spots in April and had to reseed. It may have killed some Triv, but it killed most of the good grass as well. Looked like some animal had peed in spots all Winter. One of those stupid moves everyone tries at some point.

In short, it's not worth trying.

I did spray some Tenacity in October once this year, and the whitening is still there a month later. Maybe it'll kill the target weedy grass.


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## ColeLawn (Nov 11, 2020)

Harts said:


> I wouldn't recommend Tenacity as a general post-em herbicide. It is best used during a renovation. Yes, Tenacity does bleach your good grass and it does grow out, however, there are other options out there that will get the job done.
> 
> If your lawn is really bad with weeds, you might want to consider nuking it and starting over. But first thing is to identify the weeds you have. It could be that Weed B Gon is ineffective against some weeds you are seeing. A few examples would be any grassy type weed and crab grass.
> 
> If you do plan to seed next Fall, I would hesitate to put a pre-em down as it will inhibit seed germination unless you went with a 3 month rate and over seeded in late Aug to early Sept.


Thank you for the response. And yes, the weed(s) that I am dealing with, at least in the backyard, I believe is Creeping Charlie. It's very "vine-like" and once you start pulling it it just kind of all comes out together. The front yard from what I can tell is mainly just clover and broadleaf type weeds. The front yard gets a lot of sun, the backyard gets almost no sun. The grass/soil in the backyard looks healthier though (thicker and greener) even though it is pretty weed infested.

The Weed-b-Gone hasn't done anything from what I can tell, however I didn't close on this house until the first week of October so it obviously wasn't an ideal time to be killing weeds/fertilizing.


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## Thejarrod (Aug 5, 2018)

bf7 said:


> Thejarrod said:
> 
> 
> > In addition to Harts points above, I'll add one more.
> ...


I put 2 teaspoons in a 4 gallon backpack sprayer. This is the rate on the syringe that comes with tenacity. i used teejet red tip. and yes, that is tttf. regretfully, i did NOT add triclopyr to the mix this time, which as been shown to reduce bleaching. previous applications that did include triclopyr had much less bleaching. 
looking back, i do find it harder to make consistent application on the spot treatments. its actually easier to apply consistently when doing blanket applications. if i ever use it again, i'll switch to a different teejet tip because i think it went down too heavy. maybe i'll use the yellow.


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## Harts (May 14, 2018)

@ColeLawn look at getting triclopyr (Weed B Gon CCO) and mixing it with your 3 way. This should help take care of 80% of what you have. Make sure to do it when the weeds are actively growing. It will likely take a few applications.


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## bf7 (May 11, 2020)

Thejarrod said:


> bf7 said:
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> > Thejarrod said:
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I know what you mean. I did some spot treatments in mid-October at the same rate as you (1/2 teaspoon into 1 gallon of water). That is supposed to cover 1k sq ft to arrive at a ~3.6 oz/acre rate. It's very easy to over-apply doing spot sprays. The actual area I sprayed couldn't have been more than 500 sq ft. I had fairly heavy bleaching in those spots but they had recovered completely 1.5 weeks after white appeared. I think KBG recovers from Tenacity quicker than TTTF.

Very minimal bleaching so far from my blanket sprays. I noticed a tiny amount on some of the tips this morning. I'm at 15 days since the first app and 6 days since the second app.


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## ColeLawn (Nov 11, 2020)

Harts said:


> @ColeLawn look at getting triclopyr (Weed B Gon CCO) and mixing it with your 3 way. This should help take care of 80% of what you have. Make sure to do it when the weeds are actively growing. It will likely take a few applications.


Thank you!


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## Thejarrod (Aug 5, 2018)

Thejarrod said:


> bf7 said:
> 
> 
> > Thejarrod said:
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I may have lucked out with a mild November. Some recovery starting to show. I also gently fluffed it with a rake. Here it is today. I'm thinking we need to leave at least 6 weeks of growing season following application to allow for full recovery.


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