# Who uses granular Prodiamine? Rates?



## Green (Dec 24, 2017)

For those who have used granular Prodiamine (doesn't matter if you're warm or cool season):

-What percent AI are you using? 
-How many lb/K ?
-What month was it applied?
-How long did the Pre-M barrier last?

Granular Prodiamine only, please. Thanks.


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## Green (Dec 24, 2017)

Here's my response:

-0.37%
-2 lbs/K
-Late Summer
-Not sure


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## Pete1313 (May 3, 2017)

Green said:


> Here's my response:
> 
> -0.37%
> -2 lbs/K
> ...


I don't use granular prodiamine, but the rate of AI you put down (11.84 oz AI) would have given you a roughly a 3 month barrier.


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## Green (Dec 24, 2017)

Pete1313 said:


> I don't use granular prodiamine, but the rate of AI you put down (11.84 oz AI) would have given you a roughly a 6 month barrier.


Good to know! I was kind of hoping it would last a while. Do you know if the rates act in a linear fashion as they're increased/decreased?


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## Pete1313 (May 3, 2017)

Green said:


> Pete1313 said:
> 
> 
> > I don't use granular prodiamine, but the rate of AI you put down (11.84 oz AI) would have given you a roughly a 3 month barrier.
> ...


My apologies, I was doing the math while I was getting ready to leave work. Double checked it and it is only a 3 month barrier for 2lbs/k of .37% prodiamine. Just changed it in my previous post. It is not linear.


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## Green (Dec 24, 2017)

Pete1313 said:


> My apologies, I was doing the math while I was getting ready to leave work. Double checked it and it is only a 3 month barrier for 2lbs/k of .37% prodiamine. It is not linear.


3 months...still pretty long.

Just curious, how are you calculating how long the barrier will last? 
Or are you going by experience/using a table to determine how long a certain number of ounces of AI lasts?


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## Pete1313 (May 3, 2017)

Green said:


> Pete1313 said:
> 
> 
> > My apologies, I was doing the math while I was getting ready to leave work. Double checked it and it is only a 3 month barrier for 2lbs/k of .37% prodiamine. It is not linear.
> ...


Used the chart from my 65 WDG label

.5 lbs/acre of 65WDG (.325 lbs AI/acre) is 3 month barrier.
For .37% prodiamine, 2lbs/k (.0074 lbs AI/k) multiply by 43.56 to convert to acre and you get .322 lbs AI/acre.

So ~4 lbs/k of .37% would get you about 5 months coverage, ~6lbs/k get you about 8 months coverage.


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## thegrassfactor (Apr 12, 2017)

Granular Pre... ARGGGGHHHHHHHHHH


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## Green (Dec 24, 2017)

thegrassfactor said:


> Granular Pre... ARGGGGHHHHHHHHHH


Not a fan?


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## thegrassfactor (Apr 12, 2017)

Green said:


> thegrassfactor said:
> 
> 
> > Granular Pre... ARGGGGHHHHHHHHHH
> ...


Do you see the inconsistency in the 2 bags? So frustrating. How do I trust it. I'm having an existential crises over granular pre.


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## Green (Dec 24, 2017)

That's crazy. I had no idea the two halves in the spreader were supposed to be the same product until you said it. Thought maybe one was Pendimethalin and the other was something else. Were those both your bags, and from the same batch?


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## Green (Dec 24, 2017)

Btw, Grassfactor...I just watched your video on Screamin' Green 16-2-3, a fertilizer that I bought about two years ago, and was super excited about, as well. Problem was, I haven't been able to find it since then. Thanks to this forum, I found out that SIteOne sells it, so I plan to use it again this year. I liked seeing your enthusiasm and the technical details about the product in your video.

Edi: just found your granular pre-M video. Watching it now for more details on what you posted above.


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## g-man (Jun 15, 2017)

Pretty much all of the lawn lawn chemicals we apply that last months follow an exponential decay curve.

For spring, Purdue recommends an 0.65ai/acre rate. You could split it in two apps within the spring app.


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## Green (Dec 24, 2017)

g-man said:


> Pretty much all of the lawn lawn chemicals we apply that last months follow an exponential decay curve.
> 
> For spring, Purdue recommends an 0.65ai/acre rate. You could split it in two apps within the spring app.


Thanks. 0.65 (of what unit?) per acre?
Do they have a recommendation for late Summer or early Fall as well? At this point, that's the only time of year I use Prodiamine, and only on areas that used to have an annual bluegrass issue. (I use Dimension in the Spring.)


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## g-man (Jun 15, 2017)

This study only did 09Apr and 01Jun with combos of prodiamine, dimension and pendi
https://turf.purdue.edu/report/2011/PDF/15_AGRY_Patton_sequential%20apps.pdf


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## GrassFarmer (Sep 21, 2017)

what i dont understand if you use .38 and a second app of .38 like purdue that only leaves you with .22 ai/acre left for fall POA premergence and be under the kbg max yearly rate. Is .22 enough for fall?


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## FuzzeWuzze (Aug 25, 2017)

GrassFarmer said:


> what i dont understand if you use .38 and a second app of .38 like purdue that only leaves you with .22 ai/acre left for fall POA premergence and be under the kbg max yearly rate. Is .22 enough for fall?


People that want full year coverage use different products, like Dithiopyr to span the gaps.


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## g-man (Jun 15, 2017)

@GrassFarmer Their report is around crabgrass and not around Poa Annua. You do bring a good point of something I have thought about in the past. I came up with this plan:

I follow their treatment 9 - first app in march of dimension (granular) 0.25 rate+ second app late May of prodiamine (0.38 ai rate). This leaves me enough to do a 0.5 rate in mid august. I found zero Poa in the mow I just did last weekend.

The last table in the report does give some insight into the effects in fall. The split app had an 87 % control in September. That is pretty good and even the single app had a 73%. One thing to keep in mind is that they did this in plots that had history of crabgrass problems. Must of our members are keeping the yards in top shape, so the crabgrass pressure is lower. I think it is balancing act between poa A and crabgrass. I think a good approach could be 3 apps of just prodiamine at 0.3ai/rate in March, Mid June, 01Sept; but I dont want to use my yard for the experiment.


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## Catlettsl (Aug 24, 2017)

What does AI mean in this thread?


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## Green (Dec 24, 2017)

Catlettsl said:


> What does AI mean in this thread?


Active Ingredient. But I'm not sure what people mean in this thread by:

"0.38 active ingredient rate"

or

"0.38 active ingredient per acre"

or

"0.38 active ingredient / rate"

I've never heard any of those 3 terminologies before. To me, there are units missing. Hopefully someone will clarify. Maybe I'm just being stubborn, but it doesn't make sense.


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## thegrassfactor (Apr 12, 2017)

Green said:


> Catlettsl said:
> 
> 
> > What does AI mean in this thread?
> ...


.38% of Pounds of active ingredient.

So if a 50lb bag of fert is a .38% rate of barricade, that bag has .19lbs of AI. If you need 1.0lb of AI to the acre, then You would need to apply ~5 bags to the acre to get your 1lb of AI.


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## g-man (Jun 15, 2017)

@Green

We are just being lazy and not typing all the information. The correct way would be:

We apply at a rate of 0.38 lb of ai / acre.

Ai = active ingredient

Using this rate info allows to ensure we are all talking the same chemical rate regardless of the application source (granular or liquid).

You need to use the percent of ai in your product to figure out how many pounds of the product to apply. It the same approach when we say, apply a 1lb of nitrogen per ksqft. You have to convert that to the actual pounds of the fertilizer you use.


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## Catlettsl (Aug 24, 2017)

Thanks for clearing that up.

So I applied the 50lb bag of Prodiamine .37 over my 10K turf at 5lbs per 1000. Therefore my AI is 1.9lbs per 1000.

Is that a good thing or bad thing?

I wasn't confident with the granulars so if or when I get some breakthrough of weeds what should my next step be.

At that rate of 1.9lbs per 1000 of AI how much coverage am I projected to get?


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## thegrassfactor (Apr 12, 2017)

Catlettsl said:


> Thanks for clearing that up.
> 
> So I applied the 50lb bag of Prodiamine .37 over my 10K turf at 5lbs per 1000. Therefore my AI is 1.9lbs per 1000.
> 
> ...


it's .37%

so you applied .185lbs of AI on your 10k sqft. that's .8lbs AI/acre. People run between .75lbs AI/acre to 2.0lbs AI/acre. You can do a second application at a half rate and get to 1.2lbs AI/acre which would be super money.


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## pennstater2005 (Jul 17, 2017)

I'm considering returning to granular as I hate spraying 15k with a backpack. But, it's so much more cost effective to spray that I'll probably end up going that route.

I see an electric push sprayer in my future.


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## Catlettsl (Aug 24, 2017)

thegrassfactor said:


> Catlettsl said:
> 
> 
> > Thanks for clearing that up.
> ...


PM'd you Grassfactor


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## pennstater2005 (Jul 17, 2017)

Math help please.....

8k to treat with .38% AI (50# bag) I want to apply at the 6 month rate. How much would I need per k?


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## g-man (Jun 15, 2017)

@pennstater2005 rough math is 1lb/ksqft per month of coverage. This will be 6lb/ksqft or 48lb for your 8k

I don't think you should do 6 months. I would do 4 (Sept to December) or even 3.5 months.


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## pennstater2005 (Jul 17, 2017)

g-man said:


> @pennstater2005 rough math is 1lb/ksqft per month of coverage. This will be 6lb/ksqft or 48lb for your 8k
> 
> I don't think you should do 6 months. I would do 4 (Sept to December) or even 3.5 months.


Okay. Why the shorter duration? About 35# then? I don't understand the calculations to get at these numbers.


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## g-man (Jun 15, 2017)

Two reasons.

First I know you have kbg, so your max yearly is 0.36oz of ai/ksqft and at most you can do is around 7 months coverage.

Second, unlikely for anything to germinate past December in your area.


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## pennstater2005 (Jul 17, 2017)

Thanks! How do you arrive at those numbers so I can figure it out on my own in the future?


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## g-man (Jun 15, 2017)

I looked at the water granular label. Max rate is 1.5lb/acre of that product that it is 65% ai.

That's 1lb ai/acre. An acre is 43.5ksqft and a pound is 16oz (dry).

That's 0.358oz ai/ksqft. (Yearly max).

Your bag is 0.38% ai by weight. 1lb x 0.0038 x 16 = 0.0608oz of ai/ksqft for every 1lb you apply. Multiply by 6 and you get 0.3648oz of ai/ksqft. So your max is right at 6lb of that product per year (account for your spring application.)


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## pennstater2005 (Jul 17, 2017)

g-man said:


> I looked at the water granular label. Max rate is 1.5lb/acre of that product that it is 65% ai.
> 
> That's 1lb ai/acre. An acre is 43.5ksqft and a pound is 16oz (dry).
> 
> ...


Thank you. Unfortunately, that goes right over my head :lol:


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## Green (Dec 24, 2017)

pennstater2005 said:


> g-man said:
> 
> 
> > I looked at the water granular label. Max rate is 1.5lb/acre of that product that it is 65% ai.
> ...


Me, too. I'm going to have to read it about 25 times. I don't feel like it, though! :lol:


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## Mrotatori (Aug 13, 2018)

my head hurts just looking at the calculation. I am in the same boat trying to do the math. I am thinking about putting Prodiamine in the spring. I have 10K in the front, probably 15K in the back and sides. I would like to try the liquid, but feel the granular is a better option. I may try liquid in the front, and granular in the back. I pay more attention to my front yard. If I wanted to get 4 months of coverage for 10K, how much liquid prodiamine would I need to apply?


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## g-man (Jun 15, 2017)

Ok, I won't share the math, just trust me.  for kbg or prg:

5g/ksqft of prodiamine 65wsg. Up to 3 times a year. This is a very small qty ( around 2 sugar packets). Each one last around 3 months.

You can do one in April for crabgrass, one in late July and one in Nov. Or one in April, early July and early Oct. Or if you have a thick stand with not weed issues, then skip the last one.


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## social port (Jun 19, 2017)

I trust g-man, even when there is no math :nod:


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## Mrotatori (Aug 13, 2018)

@g-man thank you so much
@social port I agree and his calc is much better than I would even attempt


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