# Prodiamine 65WDG Calculator



## Ware

Here is a link to a very useful tool that TLF member GrassDaddy developed to calculate application rates for the very popular Prodiamine 65WDG pre-emergent herbicide:


CLICK HERE TO ACCESS THE CALCULATOR​
To use the tool, enter:


The size of your lawn in square feet (or 1,000 if you just want to know the applicable rate per 1,000ft2)
Desired months of pre-emergent control (e.g. 6 months if you plan to apply it twice a year)
Your turf species








Once you click the calculate button, the tool will return something that looks like this:








Which is calculated from the maximum annual rates found in the Prodiamine 65WDG label:








_Disclaimer: This is a fantastic tool for calculating application rates, but should not be substituted for reading and understanding the entire product label before use._


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## kds

Thanks @GrassDaddy and @Ware!


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## desirous

Thanks @GrassDaddy! Can you also calculate the rate as fl.oz? It's a lot easier for me to measure volume of granules than weight.


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## Ware

desirous said:


> Thanks GrassDaddy! Can you also calculate the rate as fl.oz? It's a lot easier for me to measure volume of granules than weight.


I would highly recommend purchasing an inexpensive gram scale for measuring wettable granules.


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## mwemaxxowner

I am very excited to have stumbled upon this!

I've been tracking soil temps and should probably be getting my prodiamine down here within the next few weeks.

With regards to the months of coverage element of calculating my mix, I'm not sure whether to go 5 months or 6.

I've never tracked soil temps before, but anywhere from March to May can be when it starts warming up here. (SC, 1 hour south of Charlotte NC). There have been times in the past I was in the lake on a wakeboard the first week in March. This year it was May, nearly June before it was really warming up for us.

Would it be best to shoot longer and take a chance on overlapping my coverage a bit with my spring app, or would it be best to plan for 5 months of coverage and just take a chance on having a month or two with none?

Or would you just apply a 5 month dose, and apply the next round in 5 months even if soil temps haven't risen to 55 yet?

I want to do 3 apps, I think. One larger application in the fall, and 2 smaller applications in the spring/summer.


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## Lust4Lawn

Bumping this since it's that time of year. Thanks for this.


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## VALawnNoob

any guidance for say a 4 gallon backpack sprayer? for a 22k yard should I split front and back or will 4 gallons not even be enough to spray 11k sq ft?


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## dfw_pilot

@VALawnNoob its all in the tip you choose.


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## mwemaxxowner

It all depends on how fast you walk, how consistent you are, and the nozzle you use.

I recently did my first blanket spray application. I have a fairly brisk walking pace at around 3 mph, and after calibrating with the nozzle I chose I was using 0.8 gallons per 1000 square feet.


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## VALawnNoob

mwemaxxowner said:


> It all depends on how fast you walk, how consistent you are, and the nozzle you use.
> 
> I recently did my first blanket spray application. I have a fairly brisk walking pace at around 3 mph, and after calibrating with the nozzle I chose I was using 0.8 gallons per 1000 square feet.


Thank you! This rate is similar to what my experience is so far as well :thumbup:


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## Genoman

I am really liking the calculator, such a big help for beginners like me. I am not sure if this is an issue but everytime when I select St.augustine grass types, it puts it back into Kentucky Bluegrass. I don't think it's a problem as long as the calculations are working correctly.


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## rjjrmiller

How much does soil type influence the calculations? 
I mean obviously the calculator is a good estimation tool, but is it logical that with clay based soil the Prodiamine residual efficacy would last longer compared to other soils and therefore with clay we should lower the rate a little or a lot?


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## g-man

Prodiamine binds to the soil pretty good and the soil type should not matter. Follow the label rates. I use 5grams/ksqft 3 times a year for my grass type.


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