# Poa A in a thick lawn, best course of action in Fall?



## MarkAguglia (Jul 13, 2017)

Poa A is EVERYWHERE in my lawn this year. I applied Prodiamine last Fall but am guessing I was too late in September. Year after year I've been applying pre-emergents in Spring and Fall with great control of weeds, except for Poa Annua. What would be the best course of action for stopping Poa Annua this coming Fall? Should I apply Pre-emergent far sooner? I had planned to overseed this year because I have been applying pre-emergents regularly for the last few years. Should I skip the overseed? Would Tenacity and overseeding be a better option? I hesitate to use Tenacity because with fine fescues in my lawn, it turns my whole lawn white and is an eyesore for a month or 2.

Thanks for the help!


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## mzawlocki (May 21, 2018)

From what I understand, you have to get the preemergent down before soil temps hit 70 degrees.

https://www.extension.purdue.edu/extmedia/ay/ay-41-w.pdf
https://archive.lib.msu.edu/tic/golfd/article/2008apr33.pdf


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## bernstem (Jan 16, 2018)

Poa Annua will germinate any time conditions are favorable. That is mostly fall, but it also germinates in spring.

Pre-emergent in the spring and fall plus Tenacity spring and fall to kill anything that does germinate. There are millions of Poa Annua seeds in your soil. Even if the Prodiamine is 99% effective, you will still have thousands germinate. Each Annua that gets to seeding can drop thousands of seeds. The Tenacity helps kill them before that and prevent new seeds. If you truly have an infestation of Annua, you will be fighting this for years, but it should get better every year. Be patient.

If you do need to overseed, reserve more Tenacity for the fall to carry you through establishment until you can get Prodiamine down. You can apply Tenacity at seeding and again at 4 weeks (off label) at the 4Oz rate which will be both pre and post for Annua. Your PRG won't like that, but should survive if you are careful not to overapply.


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## rob13psu (May 20, 2018)

@MarkAguglia Check out this Webniar from Turfnet. Dr. McCurdy discusses germination being more dependent on available moisture, and that several factors may be the reason Poa A germinates later than once thought. Around the 6:30 mark. Interesting webinar.


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## mzawlocki (May 21, 2018)

bernstem said:


> If you do need to overseed, reserve more Tenacity for the fall to carry you through establishment until you can get Prodiamine down. You can apply Tenacity at seeding and again at 4 weeks (off label) at the 4Oz rate which will be both pre and post for Annua. Your PRG won't like that, but should survive if you are careful not to overapply.


When you say 4oz rate do you mean 4oz/acre?


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## MiloSmilo (May 17, 2020)

I'v had 99.9% success (from full blown poa )by putting down Tenacity (4oz rate without surfactant) at the time of my overseed.
And then another application of the same - about 6-8 weeks later (when it's quite cold out and the lawn is barely growing - I'm in Canada).
In the last 2 years of doing this I'v only had to pull 2 plants in the spring.
I think the last app of the Tenacity is key - something about staying in the poa longer while it's cold out?.... not sure.


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## bernstem (Jan 16, 2018)

mzawlocki said:


> When you say 4oz rate do you mean 4oz/acre?


Yes, per the label dosing is 4-8 Oz/Acre. 4Oz is actually below the label rate for most cool season turf, but works well especially if you do a second application 4 weeks later.


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## g-man (Jun 15, 2017)

@MarkAguglia you should be doing prodiamine in mid July for your weather. Sept is way too late.


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## j4c11 (Apr 30, 2017)

I've been battling Poa A for about 4 years in my back yard with Prodiamine. It's almost extinct, but I haven't been able to overseed in the Fall back there, so it's not looking its best. Prodiamine is very effective, but you get all sort of breaks in the barrier, squirrels digging, birds, etc, so some stuff makes is through. Just want to give you a heads up that it's not going to be a one season fix. But stick with it, it's a winnable battle.


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## MarkAguglia (Jul 13, 2017)

g-man said:


> @MarkAguglia you should be doing prodiamine in mid July for your weather. Sept is way too late.


Mid July..wow.. how many apps a year should I be doing? I've typically done 2 apps - Spring when Forsythia are about to bloom, and in early September. Both full rate apps. What would you suggest. I know theres yearly limits so which app should I alternate and use Dithiopyr? Thanks!!


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## g-man (Jun 15, 2017)

I do 3 apps of prodiamine at 5g/ksqft each. Early spring, may and late July.


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## MarkAguglia (Jul 13, 2017)

g-man said:


> I do 3 apps of prodiamine at 5g/ksqft each. Early spring, may and late July.


Your July app gets you through the rest of the year to next Spring? Any difference being that I use granular? Do you ever skip the July app and overseed?


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## g-man (Jun 15, 2017)

Late July covers, August, Sept and October. By November, winter is here and the odds of germination on a thick lawn are very very low. December, January and February are too cold.

I don't overseed.

Granular should work too, just divide the yearly max into 3 applications.


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## MarkAguglia (Jul 13, 2017)

g-man said:


> Late July covers, August, Sept and October. By November, winter is here and the odds of germination on a thick lawn are very very low. December, January and February are too cold.
> 
> I don't overseed.
> 
> Granular should work too, just divide the yearly max into 3 applications.


Thanks.... thinking I'll go this route rather than Tenacity and/or overseeding. Current state of my lawn:


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## bernstem (Jan 16, 2018)

Prodiamine will last anywhere from 3-7 months in most areas. How long it lasts depends on the rate applied. If you do one application of 1.5 lbs/Acre on April 1 that covers until Oct 30. If you apply 0.75 lbs/Acre in spring and then again in fall each will last for 4 months. If you apply on April 1, you are covered until August 1. If you apply July 15 then the second app has you covered until Nov 15. That leaves a bit at the end of fall where the barrier is faded. If you do three applications at 0.5, they each cover for three months. April 1-July 1, June 15-Sept 15, and then Sept 1-Dec 1, that is better coverage, but you can never overseed.


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## greencare (Sep 14, 2019)

MarkAguglia said:


> g-man said:
> 
> 
> > Late July covers, August, Sept and October. By November, winter is here and the odds of germination on a thick lawn are very very low. December, January and February are too cold.
> ...


Where exactly is the poa? I am guessing it is in the back as the front looks very thick. I find it curious that the little poa that I do have is isolated to the shadier sections of the lawn. I will be overseeding w/ starter fertilizer this fall in September even though I just put down pre-emergent last week. And again at the end of fall.


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## MarkAguglia (Jul 13, 2017)

greencare said:


> MarkAguglia said:
> 
> 
> > g-man said:
> ...


It's in areas all over the place. When I moved in about 5 years ago I seeded with cheap seed that had Poa, not knowing. Still havent ridded my lawn of it.
Here's some pics:


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## MarkAguglia (Jul 13, 2017)

bernstem said:


> Prodiamine will last anywhere from 3-7 months in most areas. How long it lasts depends on the rate applied. If you do one application of 1.5 lbs/Acre on April 1 that covers until Oct 30. If you apply 0.75 lbs/Acre in spring and then again in fall each will last for 4 months. If you apply on April 1, you are covered until August 1. If you apply July 15 then the second app has you covered until Nov 15. That leaves a bit at the end of fall where the barrier is faded. If you do three applications at 0.5, they each cover for three months. April 1-July 1, June 15-Sept 15, and then Sept 1-Dec 1, that is better coverage, but you can never overseed.


I'm going to give @g-man way a shot. I used 3 lb/K of Prodiamine in early April, I'll do another app end of May (this week when temps drop from 90!) and again in Late July. All 3 apps will be 3 lb/K which will keep me under the yearly max of 9.3 lb/K. Tired of using Tenacity and bleaching my lawn.. if I absolutely need to, I'll do it in the Fall this year or next and skip the July pre-M.


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## airgas1998 (May 1, 2019)

g-man said:


> @MarkAguglia you should be doing prodiamine in mid July for your weather. Sept is way too late.


hey gman I'm in central Iowa how do you know when to apply prodiamine. is there a certain soil temp targeted?


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## g-man (Jun 15, 2017)

@airgas1998 you want the prem before the POA a could germinate. That's is normally when the temp starts to drop and rain returns in August. Something in late July, early August should work.


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## greencare (Sep 14, 2019)

g-man said:


> Late July covers, August, Sept and October. By November, winter is here and the odds of germination on a thick lawn are very very low. December, January and February are too cold.
> 
> I don't overseed.
> 
> Granular should work too, just divide the yearly max into 3 applications.


So far, I have used Scotts Halts (Pendimethalin) twice. Once in April 16 at half rate, and once at full rate last week. Can I apply Pendimethalin again at full rate in July without causing problems?


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## g-man (Jun 15, 2017)

I'm not familiar with pendi. You will need to check the label. Dont go over the yearly application or any individual application rates.


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## greencare (Sep 14, 2019)

g-man said:


> I'm not familiar with pendi. You will need to check the label. Dont go over the yearly application or any individual application rates.


Scotts says not to apply it more than twice. I will ask them about it.


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## greencare (Sep 14, 2019)

One more question, g-man. Will poa that sprouts in spring be capable of producing seeds as fast as one that sprouts in fall?


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## rob13psu (May 20, 2018)

MarkAguglia said:


> bernstem said:
> 
> 
> > Prodiamine will last anywhere from 3-7 months in most areas. How long it lasts depends on the rate applied. If you do one application of 1.5 lbs/Acre on April 1 that covers until Oct 30. If you apply 0.75 lbs/Acre in spring and then again in fall each will last for 4 months. If you apply on April 1, you are covered until August 1. If you apply July 15 then the second app has you covered until Nov 15. That leaves a bit at the end of fall where the barrier is faded. If you do three applications at 0.5, they each cover for three months. April 1-July 1, June 15-Sept 15, and then Sept 1-Dec 1, that is better coverage, but you can never overseed.
> ...


I'm going to do the same. No overseed this year, so planning on a late July Prodiamine application. On a side note, where do you source your Prodiamine? It is hard to find around here.


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## Prospect (Mar 19, 2019)

So call me a nut job but my plan to out smart My POA problem is this. Feel free to help me out, call me out or Whatever.
Last Saturday I scarified, dropped some humic, fertilizer and seed then covered it with Kellogg lawn "Topper". My thought process is: scarifying traumatized the Poa and hopefully should be dyeing soon anyways. Seeding has about 4 months to grow before I apply a pre-emergent in the fall. Hopefully here in Washington the new seed can get some roots down and not die like in places that get a lot hotter. Therefore I've filled in some bare spots, traumatized the poa into dying and have enough time for the new seed to grow before I need to apply a pre-emergent. I can't be the only one trying to out Fox Poa.


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## Scagfreedom48z+ (Oct 6, 2018)

MiloSmilo said:


> I'v had 99.9% success (from full blown poa )by putting down Tenacity (4oz rate without surfactant) at the time of my overseed.
> And then another application of the same - about 6-8 weeks later (when it's quite cold out and the lawn is barely growing - I'm in Canada).
> In the last 2 years of doing this I'v only had to pull 2 plants in the spring.
> I think the last app of the Tenacity is key - something about staying in the poa longer while it's cold out?.... not sure.


I'm in the northeast and I'm going to be overseeding this fall. I'm definitely going to try thing.


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## g-man (Jun 15, 2017)

@greencare poa that germinates in spring ? I guess it can happen, but it will be very small going into the summer. If you irrigate, then it might survive.

The ones that germinates in the fall is large enough to drop seeds in the spring.


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## greencare (Sep 14, 2019)

g-man said:


> @greencare poa that germinates in spring ? I guess it can happen, but it will be very small going into the summer. If you irrigate, then it might survive.
> 
> The ones that germinates in the fall is large enough to drop seeds in the spring.


Thank you. So I think the best and vital step is late summer pre-emergent, and then perhaps overseed in early spring.


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## greencare (Sep 14, 2019)

g-man said:


> @greencare poa that germinates in spring ? I guess it can happen, but it will be very small going into the summer. If you irrigate, then it might survive.
> 
> The ones that germinates in the fall is large enough to drop seeds in the spring.


Just want to update on this. I saw couple of poa annua germinate in our vegetable garden. These guys were only about two inches tall and producing seeds already. I guess poa annua doesn't need two seasons to develop/drop seeds.

Hopefully, Scotts' Halts (pre and post emergent) will work in my favor if applied in late summer as this will reduce the amount of poa annua seeds in the lawn.


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## JulietAlpha (Jun 5, 2018)

bernstem said:


> Prodiamine will last anywhere from 3-7 months in most areas. How long it lasts depends on the rate applied. If you do one application of 1.5 lbs/Acre on April 1 that covers until Oct 30. If you apply 0.75 lbs/Acre in spring and then again in fall each will last for 4 months. If you apply on April 1, you are covered until August 1. If you apply July 15 then the second app has you covered until Nov 15. That leaves a bit at the end of fall where the barrier is faded. If you do three applications at 0.5, they each cover for three months. April 1-July 1, June 15-Sept 15, and then Sept 1-Dec 1, that is better coverage, but you can never overseed.


I'm new to this, so this may be a dumb question. I'm getting that prodiamine max rate is 15g/ksqft for the year. So three applications would be 5g/ksqft. How much water does it take per ksqft? Is there a rough number to start with, then dial in your specific sprayer to see what you require to cover 1ksqft?


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## ABC123 (Jul 14, 2017)

The lable states 1.5lb/a max rates for several cool season types. I would do the 1 tbs per gallon per 1000sq ft rate.


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## bernstem (Jan 16, 2018)

JulietAlpha said:


> bernstem said:
> 
> 
> > Prodiamine will last anywhere from 3-7 months in most areas. How long it lasts depends on the rate applied. If you do one application of 1.5 lbs/Acre on April 1 that covers until Oct 30. If you apply 0.75 lbs/Acre in spring and then again in fall each will last for 4 months. If you apply on April 1, you are covered until August 1. If you apply July 15 then the second app has you covered until Nov 15. That leaves a bit at the end of fall where the barrier is faded. If you do three applications at 0.5, they each cover for three months. April 1-July 1, June 15-Sept 15, and then Sept 1-Dec 1, that is better coverage, but you can never overseed.
> ...


1 gallon/1000 square feet give or take a bit is a good carrier volume.


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## JulietAlpha (Jun 5, 2018)

My 2 gal hand pump sprayer might need an upgrade to a backpack style! Have 13k to cover.


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## Jp6940 (Aug 11, 2019)

Have you guys looked into Anuew for poa?


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