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Discussion Starter · #1 ·
What are the best strategies to use when it comes to using glyphosate to kill Triv? I want to get a complete kill. I'm concerned about the mixing ratio, surfactant type, adjuvants, application temperature, repeat interval, and any other factors. I have hard water.
 

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Add 1 gal of water to a sprayer. Add 2.5 oz of ammonium sulfate. Mix until dissolved. Add 3.6 fl oz of 41% glyphosate or follow labels for other concentrations. If you wish to store it, use a ph meter to test it. If the ph is between 5-6, it'll be most stable. If it is higher, add a small quantity of citric acid and mix well. Retest it. If your water was ph 7 to start, you should be between 5-6 already. Now, add 0.5 fl oz non-ionic surfactant. Mix. Add 0.5 fl oz marking dye if desired. Shake sprayer before use.

I mix a few gallons and use it as needed. I have a dedicated sprayer for this. If you reuse your sprayer for other products, make sure to use a rinse aid or you may be sad later...

Spray when the plant is growing. Simple. In the 50's it may take several weeks. In the 70's and 80's you will start seeing results in a few days. Make sure the plant is dry before spraying and you want a few hours of dryness after. So, time it between rains for max absorption. 1 app is usually enough for poa. Bermuda may take 3 apps at 2 week intervals during their growing season.
 

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Discussion Starter · #3 ·
Great tips! I bought a sprayer to use just for glyphosate. I have the 41% glyphosate, ammonium sulfate, NIS, and tracker dye ready to go. I'll see if I can find some pH testing stuff as well.

Any other tips from anyone?
 

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Discussion Starter · #5 ·
Suburban Jungle Life said:
Sorry. I didn't explain the reasons for the AMS. Not sure if you wanted all that other info...
Yeah, that would be great.
 

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Adding AMS will overcome negative interactions with salts present in the water. Calcium, magnesium, sodium, and potassium have all been reported to reduce the efficacy of weak acid herbicides. AMS in a spray tank solution with calcium, magnesium, sodium, or potassium present has been shown to counteract this antagonistic effect. Researchers found that plants would absorb salts of glyphosate much more readily if the glyphosate ion is bound with ammonium compared to sodium or calcium. When glyphosate is mixed with water that contains calcium and sodium ions, calcium and sodium glyphosate salts will form as the drop dries on the leaf surface. If AMS is added, calcium sulfate and ammonium glyphosate form instead of sodium or calcium glyphosate. Glyphosate bound with ammonium instead of calcium or sodium will be taken up at a greater rate into the plant. Once the glyphosate salt enters the plant it will separate from its attached ion and begin to take its effect. Adding AMS to your tank mix can increase the amount of herbicide that will enter the plant tissue and increase levels of control if high levels of these ions are present in your water supply. Do you always need to use AMS? No, but concentrations of calcium as low as 150 ppm have been shown to antagonize glyphosate.
 

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Discussion Starter · #7 ·
Interesting! So, maybe I should use filtered water (carbon filter for drinking water) and slightly heat it in the microwave to improve solubility of AMS...what do you think? I guess if I can get some pH testing stuff, I could check the pH of both the unfiltered and filtered water to help decide which to use. I really want this to be effective.
 

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If you are really concerned about being effective, you could always mix another herbicide with a different MOA into the mix. But, your reseeding interval will be extended. You can seed the same day you spray glyphosate but if you add another herbicide, you may have to wait 30 days or longer. Or, just respray it 2 weeks later if you don't see enough of a result. That's what I do. You'll have a brown straw mat soon enough...
 

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Discussion Starter · #9 ·
I think I will do a follow-up spray two weeks later, even if it doesn't look it needs it at the surface.
 

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Discussion Starter · #10 ·
I saw pH test kits for pool water in the hardware store for $4. Would those work ok? I used to have an aquarium, and remember using something similar.
 

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That would be interesting. If you have a soil test, you could compare them for accuracy. I'd be interested in the result!

As for dissolving AMS, it does take a few minutes of shaking the sprayer which is annoying, but I suppose you could mix it in a 5 gal bucket with a drill and then pour it into the sprayer. Hot water is just too much hassle. Others add the AMS to water and leave it until the next day to add everything else. You can also buy spray grade AMS which is ground really small but I'm cheap and just use what I have. Plus, the spray grade costs more...
 

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Discussion Starter · #12 ·
You mean test the pH of my soil with the pool test kit to see if it lines up with my soil test? I don't think that would work, because the test kit uses liquid indicators that turn the water a certain color. I don't think you can test dirt!

I've never had an issue dissolving Ammonium Sulfate, but I've only done it a handful of times. I usually start with some hot water.

My biggest issue now is that the Triv is no longer bleached, so can't tell where it is anymore. I'm hoping to get down another Tenacity app tomorrow.
 

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Normally I Glyphosate at 2x strength and make sure to hit 6 inches past the border of the patch. Then I slice it out and remove the top 1-2 inches of the patch, refill with topsoil. This works but then you gotta plug and reseed a pretty big hole.

This year I tried the full dosage Tenacity approach and it seems to have killed the triv. We'll see if it comes back but right now it's mostly dead. The only problem with letting it wear off is you used up (wasted) a portion of the annual limit. I would make sure to use the entire 16oz/A in small repeated doses over 1-2 weeks.
 

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Green said:
You mean test the pH of my soil with the pool test kit to see if it lines up with my soil test? I don't think that would work, because the test kit uses liquid indicators that turn the water a certain color. I don't think you can test dirt!
:D I imagine you would have to put dirt and water in a jar, then mix well and let it sit overnight. Mix again the next day, then test the water. Of course, you need ph 7 water to start.
 

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Miggity said:
LIgrass said:
...This year I tried the full dosage Tenacity approach and it seems to have killed the triv. We'll see if it comes back but right now it's mostly dead.
Did the full dosage of Tenacity actually end up killing the triv? I have read that it turns it white but it recovers.
Nope. It looked dead for so long but came back with a vengeance. I thought my KBG would fill in but there's something with those patches (too dense) that the KBG doesn't spread into them while the Triv is temporarily dead.
 

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My experience with poa trivialis is that Tenacity doesn't kill it. The blades of the trivialis may all die, but it will come back from the roots again during the next cool, wet season.

After trying various approaches over the last few years, I now have what I think is a workable plan, which is very similar to what ligrass describes:

LIgrass said:
Normally I Glyphosate at 2x strength and make sure to hit 6 inches past the border of the patch. Then I slice it out and remove the top 1-2 inches of the patch, refill with topsoil. This works but then you gotta plug and reseed a pretty big hole.
I did almost the above on many patches in my front yard last fall. The poa trivialis has not returned in those spots. Here is what I did:

  • Glyphosate all poa trivialis you can recognize, plus 8 inches beyond the perimeter of any poa trivialis you can identify.

  • 7 Days later, repeat the glyphosate treatment again on all the mostly-dead-looking poa trivialis.

  • After the glyphosate dries (or a few days later if I didn't have time yet), cut out the dead poa trivialis with a sod cutter. Get rid of this evil sod. (I dump it way off in the woods on my property, far from the lawn!)

  • Transplant in good sod (also cut with the sod cutter) from a "donor section" of my lawn.

  • Water the transplanted sod as you would a new sod installation and enjoy the fact that the poa trivialis was eliminated in just a week, and won't be coming back!

Last fall, I did the above with a rented power sod cutter, as I had another project which required the sod cutter. For the future, I'm planning to purchase a manual kick-type sod cutter.

For future battles with poa trivialis I'm setting up a section of my lawn which is less visible from the street and a good place to grow new grass from seed (actually, it's where I used to have a vegetable garden). I'm planning to call this section of my lawn "the sod farm" and will be setting it up so that it gets good watering from just 1 or 2 sprinkler heads, so that I can water it for seed germination in the fall without having to overwater an entire zone. This will be the "donor section" of my lawn, to be used to grow sod to replace any sections of the front lawn that are killed off and replaced to combat poa trivialis.
 

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Discussion Starter · #19 ·
I actually didn't end up doing it this Spring. I might have to do some in the Fall, though.
 

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Suburban Jungle Life said:
Add 1 gal of water to a sprayer. Add 2.5 oz of ammonium sulfate. Mix until dissolved. Add 3.6 fl oz of 41% glyphosate or follow labels for other concentrations. If you wish to store it, use a ph meter to test it. If the ph is between 5-6, it'll be most stable. If it is higher, add a small quantity of citric acid and mix well. Retest it. If your water was ph 7 to start, you should be between 5-6 already. Now, add 0.5 fl oz non-ionic surfactant. Mix. Add 0.5 fl oz marking dye if desired. Shake sprayer before use.

I mix a few gallons and use it as needed. I have a dedicated sprayer for this. If you reuse your sprayer for other products, make sure to use a rinse aid or you may be sad later...

Spray when the plant is growing. Simple. In the 50's it may take several weeks. In the 70's and 80's you will start seeing results in a few days. Make sure the plant is dry before spraying and you want a few hours of dryness after. So, time it between rains for max absorption. 1 app is usually enough for poa. Bermuda may take 3 apps at 2 week intervals during their growing season.
If the ph of your water is higher than 7, does it decrease the effectiveness of glypho? I sprayed all the poa and bentgrass this past weekend. I'm questioning myself why I didn't add citric acid!
 
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