Glyphosate lingo / concentration %

Wind Gypsy

5 year old buck +
I read a lot of people saying use "2 quarts of glyphosate per acre" and similar. When they say this, is it to be interpreted as 2 quarts of 100% glyphosate or 2 quarts of a commonly diluted ratio? For example, roundup pro concentrate is roughly 50% glyphosate so would the expectation be that you apply 4 quarts of roundup pro to get to "2 quarts per acre" or is that 2 quarts assumed to be at a common concentration ratio already?
 
I read a lot of people saying use "2 quarts of glyphosate per acre" and similar. When they say this, is it to be interpreted as 2 quarts of 100% glyphosate or 2 quarts of a commonly diluted ratio? For example, roundup pro concentrate is roughly 50% glyphosate so would the expectation be that you apply 4 quarts of roundup pro to get to "2 quarts per acre" or is that 2 quarts assumed to be at a common concentration ratio already?
That would be diluted. Specifically if your looking at a smaller plot it's easier to calculate ounces per gallon.

For instance I use 3-6 oz per gallon and then make sure to use the entire mixture on my plot.

So if I have extra by the time I'm done walking I keep going otherwise you're not get total coverage.

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The amount of glyphosate you use should come from the label an your specific application. In general, when folks are talking about 2 qt/ac, that referencing the typical 41% glyphosate label. You don't use oz/gal for ag/food plot applications. You need to calibrate your sprayer. You need enough water to get even coverage of the product. The key is the amount of product per area, not how much product per gal or how many gal of water you use.

The 2 qt/ac assumes the common concentration of 41%.

There are several methods to calibrate your sprayer. I use the 1/128 acre method. You can find formulas on line for it. Basically, you fill your sprayer with water and fix the pressure setting then measure a distance specified by the formula and drive it timing yourself with a stop watch. You then stop the tractor and keep the pump going at the same rate and collect water for that time period your measured from one nozzle of your sprayer. You plug that time back into the formula and it will give you how much fluid your sprayer puts out per acre.

Once you know this, you are calibrated. If you are going to spray one acre you put in that much water and 2 quart of 41% gly (if that is appropriate for your application). If you are gong to spray 2 acres, you double the water and double the gly. You now have the ratio of gly to water that works for your sprayer.

41% gly has about 80% of the gly that is in 50% gly, so instead of using 2 qt/ac of 50% you would use about 1.6 quarts/ac.

Thakns,

Jack
 
The amount of glyphosate you use should come from the label an your specific application. In general, when folks are talking about 2 qt/ac, that referencing the typical 41% glyphosate label. You don't use oz/gal for ag/food plot applications. You need to calibrate your sprayer. You need enough water to get even coverage of the product. The key is the amount of product per area, not how much product per gal or how many gal of water you use.

The 2 qt/ac assumes the common concentration of 41%.

There are several methods to calibrate your sprayer. I use the 1/128 acre method. You can find formulas on line for it. Basically, you fill your sprayer with water and fix the pressure setting then measure a distance specified by the formula and drive it timing yourself with a stop watch. You then stop the tractor and keep the pump going at the same rate and collect water for that time period your measured from one nozzle of your sprayer. You plug that time back into the formula and it will give you how much fluid your sprayer puts out per acre.

Once you know this, you are calibrated. If you are going to spray one acre you put in that much water and 2 quart of 41% gly (if that is appropriate for your application). If you are gong to spray 2 acres, you double the water and double the gly. You now have the ratio of gly to water that works for your sprayer.

41% gly has about 80% of the gly that is in 50% gly, so instead of using 2 qt/ac of 50% you would use about 1.6 quarts/ac.

Thakns,

Jack

Excellent explanation Jack...

IMG_1600.jpg

and once you have calibrated your sprayer, make NOTE of it so you can easily refer to it next year.

IMG_2808 (1).jpg
 
Here is what I did. I filled my 25 gallon sprayer with just water and sprayed a corner of the field until it ran out several times at different speeds then measured the area sprayed. Going really slow was 1 3/4 acre and really fast was a little over 2 acres . I deducted that a gallon per tank was good and it has worked out for me .

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Excellent explanation Jack...

View attachment 37056

and once you have calibrated your sprayer, make NOTE of it so you can easily refer to it next year.

View attachment 37057
To chime in on Jack and WT's responses, I'd just reiterate that when spraying SMALL plots, like .5 acre or less the ounces per gallon usage tends to be easier to calculate.

However when larger fields are being sprayed, qts per acre with a calibrated sprayer is the way to go.

For instance my 4 gallon backpack sprayer is what I use for my .5 and .3 acre plots.

If using the 2qts per acre ration a lot of guys get tripped up on how to calculate that out.

1 qt of gly for .5 acre would be 8 oz of gly per gallon for me. As long as I use the entire thing, I'm set.

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Now that we have that covered, lets hit sprayer: boom v boomless

Whos firing the opening salvo?

bill
 
Oz per gal and use all the liquid in the sprayer. Ez as it gets.


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Oz per gal and use all the liquid in the sprayer. Ez as it gets.


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Oz/gal is not for spraying fields. It is generally for home owner or spot spraying. Let's see why.

Suppose I have a 10 gal sprayer and I choose 10 oz/gal. If the pressure in my sprayer tank and the speed I'm driving allow me to cover 1 acre with that 10 gal, I've just sprayed 100 oz/ ac which is about 3.1 qt/ac. Now, suppose I drive slower and/or have lower pressure in the tank and that 10 gal covers 2 acres. I've now sprayed 50 oz/ac or 1.56 qt/ac.

That is the whole point of calibrating a sprayer. I suggested one method and ozarkpugs suggests another. Both work and there are other methods. Unless you know your sprayer's output, oz/ac doesn't yield a consistent result.

Thanks,

Jack
 
Let’s say the plot is 1/2 acre. I put 1 quart of gly in the tank top it off with water and drive around spraying until the tank is empty.

End result? Dead shit everywhere.

Maybe the plot is 1 acre. We’ll put 2 quarts of gly in the tank top off with water and drive around spraying until the plot is empty.

Same results.

I get what your after but some of us are members of the real world.


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Let’s say the plot is 1/2 acre. I put 1 quart of gly in the tank top it off with water and drive around spraying until the tank is empty.

End result? Dead shit everywhere.

Maybe the plot is 1 acre. We’ll put 2 quarts of gly in the tank top off with water and drive around spraying until the plot is empty.

Same results.

I get what your after but some of us are members of the real world.


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In full disclosure of being an east texas bumpkin, I do the same with similar results

bill
 
I use 2.5-3 oz 0f 41% gly per gallon of water and get 1-1.5 acre of coverage. Use this in both my 25 gal tank with boom and my 4 gal backpack sprayer.
 
Calibration is definitely ideal but not possible on my hilly plots with a 3 gallon backpack sprayer or my 26 gallon ATV sprayer. I still make an attempt to distribute 2-4 quarts/acre but it’s not possible to evenly distribute without flipping my ATV.


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Calibration is definitely ideal but not possible on my hilly plots with a 3 gallon backpack sprayer or my 26 gallon ATV sprayer. I still make an attempt to distribute 2-4 quarts/acre but it’s not possible to evenly distribute without flipping my ATV.


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Had the same problem spraying on hills here with my ATV sprayer weekender. When you are getting down to the last 5 or so gallons and the sprayer tilts sideways you can’t suck up anymore solution until you get level again. Finally invested in the larger capacity 3 Pt mounted sprayer and haven’t looked back. Probably not practical for those who are only planting a few acres but it works well for me. Also now spraying a 20’ wide swath instead of 10‘ and I can maintain a constant speed with the tractor throttle which is more difficult to do on the ATV.
 
Let’s say the plot is 1/2 acre. I put 1 quart of gly in the tank top it off with water and drive around spraying until the tank is empty.

End result? Dead shit everywhere.

Maybe the plot is 1 acre. We’ll put 2 quarts of gly in the tank top off with water and drive around spraying until the plot is empty.

Same results.

I get what your after but some of us are members of the real world.


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True, but what you describe is not an oz/gal application. It is a crude qt per acre method. In your example, you define the acreage by the size of the plot and then adjusted the gly quarts of gly to match that acreage.

The reason I say crude is this. In your example, you drive through the field until the tank is empty. If it takes an even number of passes to do that, you have applied the amount of gly you want to the field. If you only get around 1 1/2 times and the take is empty, you have applied 1 qt/ac to half the field and 2 qts/ac to the other half.

Why does this matter? In the short run, and depending on your weeds, it may not. But, in the long run any weed that is not killed by the gly wasn't killed was more resistant to the gly than its cohorts that were killed and it is the one that propagates where they don't over the long run, gly resistance occurs faster than if we apply the correct amount.

I will say, few food plotters truly understand their weeds and what application rates we should apply. Few read the complex labels and understand them. That doesn't say we should not strive to do our best at it.

Everyone takes short-cuts somewhere on best practices. That is the real world. We all know that. However, those short-cuts do have consequences. We should make clear to new folks what the best practices are like calibrating your sprayer and help them learn how to do that. When we talk about short-cuts, we should make clear that there are downsides and what they are.

Thanks,

Jack
 
I didn't expect this level of feedback but thanks guys.

Thus far i've just filled the tank of the sprayer with the gly/water ratio from the label and driven around until I feel everything has been covered. It seems to work fine but just wanted to make sure there wasn't more to it. I've read the labels closer and might put more thought into it going forward.

Wanted to run a tank of water through the sprayer to clean it last night (is this necessary?) so I timed how long it takes to spray a full tank (15 gal). Figured with my 2 nozzle boom @ 5 MPH I can conservatively get full coverage on 0.45 acre which is about on the nuts with what a tank lasted me in practice. Going off the label mixture % of roughly 2 oz/gallon, I ended up near the often quoted 2 quart per acre, i just didn't calculate it out previously.
 
I use the 1/128 method on my plots. I found this method super easy after spending years trying to figure out how to calibrate my sprayer using more difficult methods. I use to fill the tank and drive until empty because I did not know how to calibrate my sprayer. I'm not saying those of you that use the drive until empty method don't know how to calibrate a sprayer, I'm just talking about me. Sometimes necessity dictates the methods we choose. I know you still get dead stuff by filling a tank and driving around until your tank is empty works but it is not efficient as jack and others have pointed out.

Sometimes you have no choice and you just do what you gotta do. I have found that some things in life you have to figure it out and adapt. I may have taken the comment wrong but it has nothing to do with living in the real world if you choose one method over the other.
 
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