# First venture into WDG



## kolbasz (Jun 7, 2017)

So today was my first time with prodiamine wdg.

Because I have never used it, I am asking for advice after my first application. A bit out of order, so I am just trying to confirm I did it right.

It's product per 1k regardless of water, right?

So I put 4oz on 6k and the about 4.5oz on 7k. Both with about 4.5gal water.

On the 6k I had a little left so I went back over some known trouble spots.


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## g-man (Jun 15, 2017)

Water is not that important as long as you could apply it without running short or with too much extra.

My only comment is your rate. It seems to be 0.85 oz / k. That seems high for Kbg.


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## Ware (Jan 28, 2017)

Agree, I think you exceeded the max annual application rate for your turf species with a single application. It looks like you were in the 0.64-0.67 oz/k range. Per the label, the max annual rate for KBG/Rye is only 0.55 oz/k, which you would ideally split into multiple applications throughout the year. I don't know what the best answer is now that it's already done, but I would probably shop for a different pre-e for subsequent applications.

You are correct in that the amount of carrier (water) doesn't matter as much as the application rate of the active ingredient. Some products specify on the label how much carrier should be used, some don't. Keep in mind the Prodiamine will need to be activated by at least 0.5 inch of rainfall or irrigation within 14 days following application.


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## g-man (Jun 15, 2017)

Wow, my metal math was way off. I think I calculated 10k instead of 13k.

Too many piña coladas and mojitos during this vacation.


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## Budstl (Apr 19, 2017)

This makes my brain hurt. I need more beer. No more vaca for gman either.


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## kolbasz (Jun 7, 2017)

Well, that sucks. I don't know what I was thinking. I was not paying attention I guess to the grass/vegetation type etc for the application rate. I just opened the book and saw .87 max rate and did 6x.8, backed it off a little and went 4 oz.

At no point did I think about a Max per year. In fact I was thinking since I'm always fighting POA a that I'd do it again in a few weeks...

Guess I'll toss that idea out the window. Good thing my spring app was dimension.

So yeah I guess the question now is what does this actually mean for me, my grass and the yard in general.


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## j4c11 (Apr 30, 2017)

I looked and was able to find some information on the effects of various pre-emergents on Kentucky Bluegrass. The whole thing is a very interesting read.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.553.3928&rep=rep1&type=pdf

tl;dr

The maximum rate for KBG is 1.5lbs/acre which is about 1.7 kg/ha.
You applied 2.30lbs/acre which is about 2.6 kg/ha.

The chart below show the "effect of prodiamine on the tiller numbers, rhizome numbers, dry
weight of tillers and dry weight of roots of Kentucky bluegrass as observed 12
weeks after treatment".



So it looks like you should expect poor density, poor root development and poor to no spreading. 
I also read somewhere that because of its effects on the roots, necrotic ring spot can be much more prevalent the following season.


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## kolbasz (Jun 7, 2017)

So, what you are saying is that I just totally f-ed myself.

Especially considering that I just liked some POA t and ripped out some bent with plans for the kbg to spread and fill it out.


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## Redtenchu (Jan 28, 2017)

What kind of spray tip did you use? What else was mixed in the tank?

DO NOT WATER IT IN!

I believe after 2 weeks the any Prodiamine that hasn't been washed into the soil should begin to break down and will mitigate the effects of over application.


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## Redtenchu (Jan 28, 2017)

You should also consider mowing a little lower than normal (not a scalp) and collecting the clippings. This will also help to remove some product from the lawn.


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## g-man (Jun 15, 2017)

Budstl said:


> This makes my brain hurt. I need more beer. No more vaca for gman either.


Vacation is over. Flying back today, hopefully to a fungus free lawn.


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## kolbasz (Jun 7, 2017)

I can turn off the irrigation system, but there is no stopping mother nature.

It was a full cocktail, prodiamine, propocanizole, tenacity and surfactant.


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## pennstater2005 (Jul 17, 2017)

I did the same thing, went to heavy, on the first couple thousand square feet. But, I believe mother nature saved me. We had a torrential downpour same today before it completely dried.


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## g-man (Jun 15, 2017)

kolbasz said:


> So yeah I guess the question now is what does this actually mean for me, my grass and the yard in general.


Do what Redtenchu suggested. His advice is spot on. I would consider the intensive nitrogen.

PS I'm going bold the PreM rate in the article.


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## kolbasz (Jun 7, 2017)

g-man said:


> kolbasz said:
> 
> 
> > So yeah I guess the question now is what does this actually mean for me, my grass and the yard in general.
> ...


I forgot, I also threw down a bag of, 25-0-6


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## g-man (Jun 15, 2017)

How many pounds to the bag? Over the 13k area?


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## kolbasz (Jun 7, 2017)

50# bag marked for 12,500 sqft


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## kolbasz (Jun 7, 2017)

If needed, I do have 9 bags Milo in the garage, which were for later, but whatever it takes not to destroy the lawn


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## g-man (Jun 15, 2017)

Not now. All the fertilizer will need water to activate and we want to avoid water.


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## kolbasz (Jun 7, 2017)

Never thought I'd be saying I hope it doesn't rain


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## Redtenchu (Jan 28, 2017)

Did you have time to mow and collect the clippings?


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## kolbasz (Jun 7, 2017)

No, just cut yesterday, from 3.5 to 3. Today I was in the attic adding a vent to the sink and washer.


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## kolbasz (Jun 7, 2017)

Redtenchu said:


> Did you have time to mow and collect the clippings?


broke down last night and told the wife about the mistake. told her I need to cut the grass again. got the green light for today after work, 3" down to 2.5


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## Redtenchu (Jan 28, 2017)

kolbasz said:


> Redtenchu said:
> 
> 
> > Did you have time to mow and collect the clippings?
> ...


I think that's a good first step. If you have time go over the lawn twice collecting the clippings both times. I think you'll be okay.


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## kolbasz (Jun 7, 2017)

Redtenchu said:


> I think that's a good first step. If you have time go over the lawn twice collecting the clippings both times. I think you'll be okay.


I hope...

Worst case, what, KBG spread is reduced?

Can the grass die?
Would it just brown and recover?
Slowed growth?

What is my future? If I just exceeded my Calendar year app, what am I to do in the spring? I am obviously going to skip a second fall treatment...

note to self, pay more attention when reading the label.


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## g-man (Jun 15, 2017)

^ I think none of us will have the knowledge around what will happen. Find the university studies that show the issues and read them in detail. They might have pictures and some of the researchers could answer some questions via email. We will be learning from you on this one. In example: more nitrogen or less? I have no clue, part of me agrees with virginagal of not adding stress, on the other it might help push some growth. We will all give you our ideas and try to help along the way.

In the research / scientific world this is called a Case Study.


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## Redtenchu (Jan 28, 2017)

+1


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## kolbasz (Jun 7, 2017)

Just consulted a horticulture specialist and his belief is this:

1. the dew on the grass is already activating the product and putting it in the ground, so cutting may do little
2. he does not think the grass will actually die
3. the cooler temperatures expected for the next week will be good
4. if really concerned he recommends lots of water vs less
5. says I can always aerate to break the barrier
6. does agree that root growth can be impacted
7. does agree with potentially less rhizome activity 
8. he says I am thinking too much and while it is over applied, he does not expect a catastrophe
9. if the grass is not already showing signs of stress/dying I should be OK
10. he did not seem overly concerned for me

So, time will tell I guess?


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## ericgautier (Apr 22, 2017)

Good info! Following as I am curious to see what happens. I'm hoping for the best!


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## kolbasz (Jun 7, 2017)

Redtenchu said:


> kolbasz said:
> 
> 
> > Redtenchu said:
> ...


Ok, just cut from 3 down to 2.5. the rest is wait and see


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## kolbasz (Jun 7, 2017)

Staying at 2.5" thinks are still alive. This is a plus, but other than everything not being dead, I cannot say much.

I mowed this weekend and thinks looked very like. Not sure if this was lack of water or what, but it is still there and growing, so we shall see.

About the only plus is I found a crap ton of bent grass. I knew there was a lost, but yesterday (8-9 days after app) you can really see the patches. So much I am debating another blanket application as opposed to just attacking the spots and then missing some. Thinking the 2oz/Acre rate vs 4. That is right, right? So like 1.7 tsp for 6k


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## g-man (Jun 15, 2017)

I think you are discussing Tenacity, correct? I prefer the 2oz/acre rate for spot treatment and to light up the problem areas.

Use this to calculate tenacity. http://thelawnforum.com/viewtopic.php?f=9&t=921


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## kolbasz (Jun 7, 2017)

g-man said:


> I think you are discussing Tenacity, correct? I prefer the 2oz/acre rate for spot treatment and to light up the problem areas.
> 
> Use this to calculate tenacity. http://thelawnforum.com/viewtopic.php?f=9&t=921


yes, it was part of my cocktail when I went a little crazy


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