# prodiamine Fall application time



## vnephologist (Aug 4, 2017)

Wanted to take monty up on his prodiamine split offer, so was doing some research and see lots of references on when to apply in Spring, but can't find much timing info on a Fall application if splitting them up. Do I just base it on my Spring timing, i.e. Spring date minus 6 months, or can I try to better target Fall poa annua germination time (soil temperatures fall below 70°F)?


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## fusebox7 (Jul 27, 2017)

My new regimen is as follows to increase pre-M coverage by introducing split apps. My "1 in spring" and "1 in fall apps" were not very effective due to the wild back and forth climate up here.

0.3oz/k per application gives me a bit of overlap due to high watering moving the product out of the soil after awhile
1) Apply in spring after the snow melts
2) Apply in spring when the forsythia bloom
3) Apply in July
4) Apply in September (this one should be bumped up to cover me through winter (6 month rate?)


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## ken-n-nancy (Jul 25, 2017)

I use prodiamine as a pre-emergent, as it is reasonably inexpensive on a per-application basis. I apply 3 times a year at the 3-month rate each time. This keeps me under the recommended maximum annual application amount and gives just about year-round coverage for the weeds I'm targeting.

I make the first 3-month rate application in the spring at the time of Forsythia bloom. This is typically the last week of April or early May for me. It will be earlier for folks further south. This application is to protect against crabgrass and other early summer weeds.

I make a second 3-month rate application at the beginning of August to protect against _Poa annua_ in early fall. I then make a second 3-month rate application around October 1st to provide additional protection against _Poa annua_ in late fall. At a 3-month rate, that should last until Jan 1st.

There are many other reasonable approaches, depending upon one's goals and primary weed threats in your area for your lawn.


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## g-man (Jun 15, 2017)

I follow K&N plan but I use dimension granular early spring since it is easier to apply (no cleaning of tanks, wands, etc), plus I could do year long coverage. Do, early spring (dimension), May (prodiamine), August (prodiamine), and Oct (prodiamine). These dates have to be adjusted for your weather/location.


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## GrassDaddy (Mar 21, 2017)

Poa annua germinates at 70 degrees (soil temp) so ideally you would apply it before then.


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## vnephologist (Aug 4, 2017)

g-man's early spring (dimension), May (prodiamine), August (prodiamine), and Oct (prodiamine) sounds like a good plan. I've only found two poa annua plants so far and find it hard to believe that I completely killed my small outbreak with only Tenacity last Fall, so I think I still have time. I guess the Davis soil temp sensor is handy for this use case as well.


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## GrassDaddy (Mar 21, 2017)

Now that is cool!


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## TulsaFan (May 1, 2017)

GrassDaddy said:


> Poa annua germinates at 70 degrees (soil temp) so ideally you would apply it before then.


If I was looking at Mesonet, would I look for the 2", 4", or 10" soil temperature?


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## Matthew_73 (Jul 9, 2019)

g-man said:


> I follow K&N plan but I use dimension granular early spring since it is easier to apply (no cleaning of tanks, wands, etc), plus I could do year long coverage. Do, early spring (dimension), May (prodiamine), August (prodiamine), and Oct (prodiamine). These dates have to be adjusted for your weather/location.


When is too late for a Fall My reno is on Day 50.. We are in the same climate... I also have Tenacity as that will work now, but then what?


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## g-man (Jun 15, 2017)

I dont understand your question.


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## GregKeller (Sep 7, 2020)

g-man said:


> I follow K&N plan but I use dimension granular early spring since it is easier to apply (no cleaning of tanks, wands, etc), plus I could do year long coverage. Do, early spring (dimension), May (prodiamine), August (prodiamine), and Oct (prodiamine). These dates have to be adjusted for your weather/location.


Not to question your process, but would it make more sense to make the early spring app prodiamine, and the May app Dimension? Dithyopyr is effective as a post emergent against young crabgrass isn't it? It would seem to get a good pre down early (most likely before anything comes up), then the next app to extend the preemergent window, but also kill anything that came up as the prodiamine wore off. Just sort of thinking out loud.


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## kk07 (Sep 2, 2020)

vnephologist said:


> g-man's early spring (dimension), May (prodiamine), August (prodiamine), and Oct (prodiamine) sounds like a good plan. I've only found two poa annua plants so far and find it hard to believe that I completely killed my small outbreak with only Tenacity last Fall, so I think I still have time. I guess the Davis soil temp sensor is handy for this use case as well.


@vnephologist , what app is that you used to get that plot? Very nice.


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## g-man (Jun 15, 2017)

@GregKeller yes what you say makes sense. I had the granular dimension, so I wanted to avoid spraying in March.

This post is from 2017. I used all the granular and now just spray the prem.


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## GregKeller (Sep 7, 2020)

Haha, I just noticed that. Guess this thread got resurected and I didn't notice it was so old


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## Jonslawn (Apr 30, 2021)

g-man said:


> I follow K&N plan but I use dimension granular early spring since it is easier to apply (no cleaning of tanks, wands, etc), plus I could do year long coverage. Do, early spring (dimension), May (prodiamine), August (prodiamine), and Oct (prodiamine). These dates have to be adjusted for your weather/location.


G-Man you always seem to be very knowledgeable!
I have some POA Annua throughout my lawn which has came in nicely this summer (the grass that is). I am doing a fall overseed of TTTF 3 way mix mid August as I am in Ontario.

My question is, should I use my Tenacity before, after, or when I overseed to kill the POA or attempt at it this year, OR purchase some Prodiamine and apply that in August or is that a product that can be applied before seeding, during, or after?

Thanks alot eh!


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## ken-n-nancy (Jul 25, 2017)

Jonslawn said:


> g-man said:
> 
> 
> > I follow K&N plan but I use dimension granular early spring since it is easier to apply (no cleaning of tanks, wands, etc), plus I could do year long coverage. Do, early spring (dimension), May (prodiamine), August (prodiamine), and Oct (prodiamine). These dates have to be adjusted for your weather/location.
> ...


Doing an overseed when you have "_Poa annua_ throughout my lawn" is a challenging endeavor. The conditions you'll be creating to get the new seeds to germinate are exactly the conditions the _Poa annua_ seeds in your soil will want, too. Is the overseed strictly necessary, or can encouraging your existing grass through good cultural practices (proper mowing, watering, and fertilizing) be enough to achieve your objectives?

I would think that _Poa annua_ should be pretty readily identifiable in a TTTF lawn (which is my assumption given your plan for a TTTF overseed), but I see that your profile lists KBG/PRG. What is your current lawn?

Basically, if you have _Poa annua_ in your existing lawn and want to get rid of it, a multi-season multi-pronged approach is going to be necessary to be successful. What I would suggest is that whenever you see a _Poa annua_ plant in your lawn, remove it. Personally, I'm a fan of hand-pulling the worst offenders every time I mow. Combining the hand-pulling with pre-emergents and avoiding "germination conditions" have succeeded in getting the _Poa annua_ under control in our lawn.

For widespread infestations, more drastic measures will be necessary, but if you have had _Poa annua_ in your lawn within the prior few years, any time that "germination conditions" are created, the _Poa annua_ seed bank in the soil will result in a new crop of _Poa annua_ coming up with your desirable grass, too.


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## Virginiagal (Apr 24, 2017)

For anyone following along, Jonslawn has already covered the topic of his poa and use of preemergent in this thread:
https://thelawnforum.com/viewtopic.php?t=30031
And it seemed he agreed he didn't need to overseed. But now he says he is.

Jonslawn, regular preemergent (like Prodiamine) does not kill existing grass. It prevents seeds-any seeds including your grass seeds-from germinating and growing. Tenacity can be used at seeding to prevent weeds from germinating for about 30 days. It allows grass seed to germinate, so it gives the grass seeds a head start against weeds. I still don't think there is any need for you to overseed. Your pictures show full coverage. Also, in another thread you're talking about doing the nitrogen blitz. You don't do that if you're overseeding. I also think you should think twice or three times before doing so much potassium in the fall. You are subject to snow cover and fall potassium has been linked to snow mold. You can just as easily do the potassium in the spring.


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## Jonslawn (Apr 30, 2021)

ken-n-nancy said:


> I use prodiamine as a pre-emergent, as it is reasonably inexpensive on a per-application basis. I apply 3 times a year at the 3-month rate each time. This keeps me under the recommended maximum annual application amount and gives just about year-round coverage for the weeds I'm targeting.
> 
> I make the first 3-month rate application in the spring at the time of Forsythia bloom. This is typically the last week of April or early May for me. It will be earlier for folks further south. This application is to protect against crabgrass and other early summer weeds.
> 
> ...


Going to try your approach this August! Just out of curiosity are you applying prodiamine with a surfactant as well or without? Also if I blanket spray prodiamine and it lets say all of a sudden gets hot for a week will it burn the lawn?

Thanks!


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## stevehollx (Apr 8, 2020)

Jonslawn said:


> Going to try your approach this August! Just out of curiosity are you applying prodiamine with a surfactant as well or without? Also if I blanket spray prodiamine and it lets say all of a sudden gets hot for a week will it burn the lawn?
> 
> Thanks!


No surfactant-that is used for keeping chemicals on easy leaves to take in. Pre-'em is a moisture barrier in the soil so you want ground contact and want the opposite of what surfactant does. No risk of leaf burning but you want to get it watered in for the moisture barrier to set. At least .5" of gentle rain after applying within 2 weeks is the recommendation. That's probably about an hour of sprinkler time, roughly, since this also doesn't need to be a precise measurement by any means.


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## ken-n-nancy (Jul 25, 2017)

stevehollx said:


> Jonslawn said:
> 
> 
> > Going to try your approach this August! Just out of curiosity are you applying prodiamine with a surfactant as well or without? Also if I blanket spray prodiamine and it lets say all of a sudden gets hot for a week will it burn the lawn?
> ...


+1 to what @stevehollx said: no surfactant when applying prodiamine, and it won't burn the lawn, even if it never gets watered in.

However, prodiamine doesn't actually do any good until it gets down into the soil, so it doesn't really "count" as being applied until after it gets watered in...


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## Jonslawn (Apr 30, 2021)

Awesome thanks guys! Once my order ships I will put down a 3 or 4 month app and again in October


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