Sprayer calibration - 15 or 20 GPA

[kilroy60]

I've always sprayed at 20 gallons per acre. Recently had a farmer tell me that he always sprays at 15 gallons per acre. Using less water and the mix is a little hotter. He has faster and better results with this setting. Never thought about this but can see his point on less water and having a hotter mix. As soon as the rain holds up, we're going to start spraying here. Just wondering your thoughts on this and has anyone else use a different GPA on their spray system.

 

[sstterry]

I've always sprayed at 20 gallons per acre. Recently had a farmer tell me that he always sprays at 15 gallons per acre. Using less water and the mix is a little hotter. He has faster and better results with this setting. Never thought about this but can see his point on less water and having a hotter mix. As soon as the rain holds up, we're going to start spraying here. Just wondering your thoughts on this and has anyone else use a different GPA on their spray system.

Wouldn't it really depend on the Chemical being used and the Manufacturer's recommendation?

 

[M-5]

I've always sprayed at 20 gallons per acre. Recently had a farmer tell me that he always sprays at 15 gallons per acre. Using less water and the mix is a little hotter. He has faster and better results with this setting. Never thought about this but can see his point on less water and having a hotter mix. As soon as the rain holds up, we're going to start spraying here. Just wondering your thoughts on this and has anyone else use a different GPA on their spray system.

Wouldn't it really depend on the Chemical being used and the Manufacturer's recommendation?

You can mix 20 gpa to be hotter

 

[bird dog]

More liquid on the same amount of acreage results in better coverage. If you are putting out the correct amount of herbicide per acre, the more liquid the better. "Hotter" is not necessarily better. It is often just a waste of money.
In the spring and early summer you can get by with the minimum amount of herbicide the label calls for. As it gets later in the year, the plants get tougher and your mix will need to be a little "hotter".
Saying all that, I spray with 15 gallons per acre. It seems to be enough for me and what works best with my sprayer setup and the terrain I have to cover. The quality of your surfactant probably has as much to do with the results as anything. Don't go to all the expense to spray and then skimp on the surf.

 

[callmefence]

More liquid on the same amount of acreage results in better coverage. If you are putting out the correct amount of herbicide per acre, the more liquid the better. "Hotter" is not necessarily better. It is often just a waste of money.
In the spring and early summer you can get by with the minimum amount of herbicide the label calls for. As it gets later in the year, the plants get tougher and your mix will need to be a little "hotter".
Saying all that, I spray with 15 gallons per acre. It seems to be enough for me and what works best with my sprayer setup and the terrain I have to cover. The quality of your surfactant probably has as much to do with the results as anything. Don't go to all the expense to spray and then skimp on the surf.

That's exactly right. It's about how much chemical you put. A quart is a quart no matter the water. More water allows for better distribution of the chemical. And usually better effect.

 

[Brute 23]

That's a false theory. With most stuff its about coverage. Spend the money on good nozzles if you want a good kill.

I have a little TJet boomless nozzle that gets 80%+ kill at 12.5gpa. Ive rented boom sprayers that were lucy to get 50% at 20 or 30gpa.... same 2pt per acre on both.

 

[BC]

Weed specialist at TAMU once told me "The wetter the better". Most folks I know that cut back on gallons per acre are trying to cover more acres on a tank full of mix.

 

[okiek]

More liquid on the same amount of acreage results in better coverage. If you are putting out the correct amount of herbicide per acre, the more liquid the better. "Hotter" is not necessarily better. It is often just a waste of money.
In the spring and early summer you can get by with the minimum amount of herbicide the label calls for. As it gets later in the year, the plants get tougher and your mix will need to be a little "hotter".
Saying all that, I spray with 15 gallons per acre. It seems to be enough for me and what works best with my sprayer setup and the terrain I have to cover. The quality of your surfactant probably has as much to do with the results as anything. Don't go to all the expense to spray and then skimp on the surf.

+1....The chemical company I buy from (And the label on Brash I spray with) both say for thicker, heavier cover, use more water P/A. I have a hay field I spray at 10 gpa, while an 80 acre pasture is thickly covered enough it gets 20 gpa early in the year to make sure I get good penetration.

 

[Jogeephus]

Weed specialist at TAMU once told me "The wetter the better". Most folks I know that cut back on gallons per acre are trying to cover more acres on a tank full of mix.

I agree. Ideally you want to put it out just to the point of runoff but that's not always practical.

If you aren't getting a good kill with more water then you have a droplet size problem.

 

[kilroy60]

I understand all the comments but I think some are missing the main point. Either way, 15 or 20 GPA, I'd still be using the same amount of chemical but would be using less water to make the mix. Example (going from memory) I believe that grazon is 2 pints per acre (if it's something else, just bare with me for this example). Acres to spray is 15; spraying at 20 GPA; chemical amount would be 3 gal and 96 oz; water amount would be 296.25 gallons. This results in a total mix of 300 gallons.
Using the same acres and spraying at 15 GPA, chemical amount would be the same (3 gal and 96 oz) but water usage would only be 221.25 gallons resulting in a total mix of 225 gallons. The 15 GPA mix would result in being more "potent" (for lack of better words). Understand the use of the sufactant and totally agree, a good sufactant and the correct amount is very important. And also the proper nozzles as well, is a good point.
It took me a while to understand the less water point he was making to me. Just wondering others thoughts on this.

 

[M-5]

Your still putting 2 pints per acre of chem. Your just using less water which could lead to not getting proper coverage.

 

[True Grit Farms]

What weighs the most a pound of lead or a pound of feathers? Same deal.

 

[ga.prime]

If it aint broke don't fix it.

 

[Brute 23]

I understand all the comments but I think some are missing the main point. Either way, 15 or 20 GPA, I'd still be using the same amount of chemical but would be using less water to make the mix. Example (going from memory) I believe that grazon is 2 pints per acre (if it's something else, just bare with me for this example). Acres to spray is 15; spraying at 20 GPA; chemical amount would be 3 gal and 96 oz; water amount would be 296.25 gallons. This results in a total mix of 300 gallons.
Using the same acres and spraying at 15 GPA, chemical amount would be the same (3 gal and 96 oz) but water usage would only be 221.25 gallons resulting in a total mix of 225 gallons. The 15 GPA mix would result in being more "potent" (for lack of better words). Understand the use of the sufactant and totally agree, a good sufactant and the correct amount is very important. And also the proper nozzles as well, is a good point.
It took me a while to understand the less water point he was making to me. Just wondering others thoughts on this.

Your using the wrong terminology IMO. More potent means a better effect which is not really true in this case.

What I think you mean to say it it is more concentrated.

 

[kilroy60]

I understand all the comments but I think some are missing the main point. Either way, 15 or 20 GPA, I'd still be using the same amount of chemical but would be using less water to make the mix. Example (going from memory) I believe that grazon is 2 pints per acre (if it's something else, just bare with me for this example). Acres to spray is 15; spraying at 20 GPA; chemical amount would be 3 gal and 96 oz; water amount would be 296.25 gallons. This results in a total mix of 300 gallons.
Using the same acres and spraying at 15 GPA, chemical amount would be the same (3 gal and 96 oz) but water usage would only be 221.25 gallons resulting in a total mix of 225 gallons. The 15 GPA mix would result in being more "potent" (for lack of better words). Understand the use of the sufactant and totally agree, a good sufactant and the correct amount is very important. And also the proper nozzles as well, is a good point.
It took me a while to understand the less water point he was making to me. Just wondering others thoughts on this.

Your using the wrong terminology IMO. More potent means a better effect which is not really true in this case.

What I think you mean to say it it is more concentrated.

That's the word I was looking for Brute - more conentrated.

Thanks for all the comments. Just wondering how others felt and thought.