# Tenacity and surfactant



## Greensass1 (Jun 1, 2019)

So I bought tenacity and surfactant and I just wanted to know when I should spray the lawn in the spring to prevent weeds...more specifically crab grass...
I realize it germinates at 60f so I was just curious if I could use that as a pre- emergent...
Or should I just use crab X that I have instead??


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## rob13psu (May 20, 2018)

Good day! I believe that Tenacity (mesotrione) with a surfactant is used as a post emergent herbicide. You can use it without a surfactant as a pre-emergent, but I believe it only lasts for 30 days. Most use dithiopyr or prodiamine as a pre-emergent for crabgrass. I've pasted some info from the cool-season guide below.

Group: 3
Dithiopyr (Dimension)
Pre-emergent and Post-emergent. Has some post emergent activity on crab grass. Doesn't have a long lasting effect.
Pendimethalin (Pendulum)
Pre-emergent.
Prodiamine (Barricade, Resolute)
Pre-emergent. Lasts 3-8 months depending on application rate. Cheap. Apply in fall for winter weeds and apply in spring for summer weeds.

Group: 27
Mesotrione (Tenacity)
Pre-emergent, mainly to target weeds during seeding. Also targets poa annua as a pre-emergent.
Post-emergent to target mainly bentgrass and nimblewill but has some activity on poa annua and bermuda.

Here's a link to the herbicide guide. Hope that helps!


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## Greensass1 (Jun 1, 2019)

So where can the dimension or barricade be purchased??i live in Ontario where that stuff is banned...I have family that live in nyc so when I go over I stock up


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## rob13psu (May 20, 2018)

Greensass1 said:


> So where can the dimension or barricade be purchased??i live in Ontario where that stuff is banned...I have family that live in nyc so when I go over I stock up


@Harts or @Sinclair might be able to help.


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## Suburban Jungle Life (Mar 1, 2018)

I recommend prodiamine. Its cheap and will stop most weeds grown from seeds. Put it out in the early spring and it'll stop all the crabgrass and many other broadleaf weeds. It stops grass seed also so use the appropriate rate if you want to seed in the fall.

I think seedworldusa ships up north.


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## Harts (May 14, 2018)

@Greensass1 Seed World USA carries both prodiamine and dimension and will ship to us in ON. Prodiamine is a better value. Will last for years and years.


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## Greensass1 (Jun 1, 2019)

When you say grass seed you mean new grass seed being spread or it will kill prexisting grass?


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## g-man (Jun 15, 2017)

Tenacity is not a good one for long term crabgrass strategy. It only last ~30days, while crabgrass can grow for months. You will need to reapply at 30days, but you will reach the yearly max before the season ends. Only use tenacity in spring if you plan to seed(overseed) in the spring.


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## Suburban Jungle Life (Mar 1, 2018)

Greensass1 said:


> When you say grass seed you mean new grass seed being spread or it will kill prexisting grass?


New grass seed. If you have low density and want a thicker lawn, most people will put down grass seed. The prodiamine can stop that seed from growing. If you have bluegrass, then you won't need to seed since it'll spread if you fertilize it.


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## estcstm3 (Sep 3, 2019)

Suburban Jungle Life said:


> Greensass1 said:
> 
> 
> > When you say grass seed you mean new grass seed being spread or it will kill prexisting grass?
> ...


If i was to do a prodiamine treatment this spring, would that prevent me from overseeding in the fall?


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## Greensass1 (Jun 1, 2019)

Harts said:


> greensass1 Seed World USA carries both prodiamine and dimension and will ship to us in ON. Prodiamine is a better value. Will last for years and years.


 Are you sure about the seed world shipping to Ontario? Are you sure it is not banned here? Am I asking too many questions??😂😂


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## ScottW (Sep 16, 2019)

estcstm3 said:


> If i was to do a prodiamine treatment this spring, would that prevent me from overseeding in the fall?


No.
If you check the label it will tell you how much to apply to get X months of preemergence activity. For example:
On average, 1 pound per acre (0.37 oz per 1000 sqft) controls crabgrass for 5 months.
On average, 0.75 pounds per acre (0.27 oz per 1000 sqft) controls crabgrass for 4 months.
The "on average" is accounting for multiple climate types. In the transition zone and farther south it loses activity a bit quicker than up north.
Label specifically says that in the transition zone you can overseed 4 months after applying prodiamine at either of the two above rates.

You could apply prodiamine at the 4-month rate in early April, then it will wear off in time for your fall overseed. If it wears off a little early and you get some crabgrass or other weed germination before your overseed, it's not a huge problem because ideally you'll be applying Tenacity at seed-down which will suppress weeds while your new grass seed germinates.

BTW I also happen to be in NoVA (22042) and I have plenty of prodiamine. I'll happily sell you a pound if you don't want to buy your own 5-lb jug. :lol:


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## Methodical (May 3, 2018)

Suburban Jungle Life said:


> Greensass1 said:
> 
> 
> > When you say grass seed you mean new grass seed being spread or it will kill prexisting grass?
> ...


This is why I miss using bluegrass. I will be spreading it again this spring to get it back in my lawn.

OP, as already mentioned, Prodiamine is the better choice and will last a long time, if you can get your hands on some.  It works. I applied in the fall and have not seen any of those weeds that typically spring up this time of the year.


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## estcstm3 (Sep 3, 2019)

ScottW said:


> estcstm3 said:
> 
> 
> > If i was to do a prodiamine treatment this spring, would that prevent me from overseeding in the fall?
> ...


Hey Scott that would be awesome, ill PM you! Yeah I grew up in Fairfax (22030), but then moved to florida for the last 9 years, St Aug is easy peazy. Taking care of the northern mixes defintely requires more work. I already have tenancity and I have access to awesome seed out of maryland. "The Mill" it 3 way TTTF blend with cutivalrs only on the Virginia Tech reccomended list, with 0 weed and 0 other crop seed. Very reasonably priced too. Anyways this is a great thread and I want to make sure im doing the right things in order.

Is spring a a good time to try to kill off bermuda grass? Im thinking of just rounduping it out and seeding? But not sure if that should be my fall project.


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## estcstm3 (Sep 3, 2019)

ScottW said:


> estcstm3 said:
> 
> 
> > If i was to do a prodiamine treatment this spring, would that prevent me from overseeding in the fall?
> ...


Hey Scott that would be awesome, ill PM you! Yeah I grew up in Fairfax, but then moved to florida for the last 9 years, St Aug is easy peazy. I just recently boomeranged back to the area (22030) with a whole lot more yard than I had before. Taking care of the northern mixes defintely requires more work. I already have tenancity and I have access to awesome seed out of maryland. "The Mill" it 3 way TTTF blend with cutivalrs only on the Virginia Tech reccomended list, with 0 weed and 0 other crop seed. Very reasonably priced too. Anyways this is a great thread and I want to make sure im doing the right things in order.

Is spring a a good time to try to kill off bermuda grass? Im thinking of just rounduping it out and seeding? But not sure if that should be my fall project.


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## Harts (May 14, 2018)

Greensass1 said:


> Harts said:
> 
> 
> > greensass1 Seed World USA carries both prodiamine and dimension and will ship to us in ON. Prodiamine is a better value. Will last for years and years.
> ...


Yes everything Seed World sells is banned here. And yes, they ship to Ontario. I have placed 4 orders with them in the last 2 years without issue. Many other Canadians here have used them as well.

You should check out the Toronto discussion in the Hometown thread.


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## Greensass1 (Jun 1, 2019)

Oh I didn't realize there was a Toronto chat!☺
Thanks for the advice...Christ oh mighty this is starting to get more expensive than gun collecting!&#128514;
Why so expensive???


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