# What does PGR do to St Augustine?



## Ecks from Tex (Apr 26, 2018)

Has anyone ever used it on St Aug?

I have this patch of SA that just refuses to grow outward and only upward (I think due to soil conditions which I am working on). Long story short it just keeps growing upward while never thickening. Could PGR force outward growth of this patch of grass?


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## Greendoc (Mar 24, 2018)

It can. What Trinexepac does to SA is it will make the leaves small and dwarfed. Of course, the energy not used to make the long, broad leaves SA is known for theoretically should be going towards roots and stolons. However, usage rates to get this effect are 4 oz per acre or less. That translates to 1/2 teaspoon. I go even lower and start measuring with a syringe with some tubing attached. I use 2 cc per 1000 sq ft.


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## Ecks from Tex (Apr 26, 2018)

Interesting insight thanks man. I honestly may try it on a portion just to see if it thickens. I'm in my second season with this grass and it has not grown out/thickened at all. If I can't make progress this season I'm just going to re-sod.


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## Greendoc (Mar 24, 2018)

Conversely, I do not PGR healthy, thick SA. I control growth by limiting N and water.


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## Ecks from Tex (Apr 26, 2018)

@Greendoc I guess I understand what you are saying to mean don't apply to healthy parts of my lawn, only to a test area in one of the patches that will not thicken?


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## Greendoc (Mar 24, 2018)

Yes. One of my mentors, a golf super, warned me about what PGR can do to grass. It will reduce height and thicken it yes. That thickening can also translate to thatching. If it were me, I would PGR and fertilize the part of the lawn that needs work and keep the rest of the lawn on minimal Nitrogen and water.


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## BakerGreenLawnMaker (Mar 13, 2018)

Ecks from Tex said:


> Interesting insight thanks man. I honestly may try it on a portion just to see if it thickens. I'm in my second season with this grass and it has not grown out/thickened at all. If I can't make progress this season I'm just going to re-sod.


I have SA too, and I to have issues with my SA filling in bare or thin spots. This is my second year in this house and I honestly have a love/hate relationships with SA. It's not like your Bermuda and zoysia lawns, we are limited to what we can and can't do to it. I found if I hit in the beginning of the spring with a starter fert and a heavy dose of Milo, it comes in really strong end of May beginning of June. This year on the other hand I cut it really really low at the end of March to try and rid it of thatch, and threw some 16-25-12 out with a dose of Milo, the lawn right now looks to be recovering quite well. I still have a ton of weeds where there is more shade, but hopefully those weeds will be chocked out come mid summer. I do plan on throwing out some 20-0-3 by Fertilome in mid June and see if it kills all the weeds and see if it will promote growth to the SA. This is the summer of trial and error with my SA.


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## Greendoc (Mar 24, 2018)

How low and how often are you mowing? SA acts differently from other grasses in terms of how it reacts to mowing as well. One of the best things I do to a SA lawn with issues is to basically leave it alone. No more every 3-7 day mowings. Ensure it does not dry out. But otherwise stay off of it and let it grow. With that treatment, if the SA was under stress, what I see after 2 weeks of leaving it alone is a lawn about 6" tall, with the areas that were concerning me substantially repaired. BTW, low and frequent mowing often causes a thatch problem in SA. That and overfeeding. Less is a lot more when dealing with SA. I call that the lowest maintenance turfgrass. It is for people that do not want to have to mow low and mow often or even fertilize.


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## BakerGreenLawnMaker (Mar 13, 2018)

What are some inexpensive herbicides that I could use to rid my lawn of weeds. Seems like all the weed killers have 2, 4-D in them, and SA doesn't take to kindly to 24D.


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## Bunnysarefat (May 4, 2017)

Interesting about the PGR. @Ecks from Tex what kind of sun does the SA get that you're trying to get to spread?


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## Greendoc (Mar 24, 2018)

BakerGreenLawnMaker said:


> What are some inexpensive herbicides that I could use to rid my lawn of weeds. Seems like all the weed killers have 2, 4-D in them, and SA doesn't take to kindly to 24D.


Cheapest is something called MSM(Metsulfuron). However, this is something to be very careful of. It works like no other on most broadleaf weeds. It also works on your trees and shrubs as well as your neighbor's. Application rate is 0.3 gram per 1000 sq ft or 0.0125 oz. That is per 1000 sq ft not gallon. If you were to mix that in a gallon and spray weeds, that would most likely result in either burned grass or dead trees and shrubs.


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## Ecks from Tex (Apr 26, 2018)

Bunnysarefat said:


> Interesting about the PGR. @Ecks from Tex what kind of sun does the SA get that you're trying to get to spread?


Shade/less than 6 hrs a day. But there are other factors at play because I have the same grass 20 feet over under another shade tree and it grows on average 2-3.5 inches a week and is thick as hell (I constantly violate the 1/3 rule in that area), so I know the strain of grass is capable of growing thick and tall. This other area is just amuck and I'm not sure why; I am going to try PGR like Doc recommended and if that shows no improvement take a couple soil samples and probsbly lay new shade tolerant sod next year.


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## Ecks from Tex (Apr 26, 2018)

Greendoc said:


> BakerGreenLawnMaker said:
> 
> 
> > What are some inexpensive herbicides that I could use to rid my lawn of weeds. Seems like all the weed killers have 2, 4-D in them, and SA doesn't take to kindly to 24D.
> ...


Isn't that stuff pretty brutal on St Augustine? Especially in June.

I've come to believe you just shouldn't spray post-emergent herbicide in June unless you are having to fight a lawn killer like torpedo grass or Virginia Buttonweed. Spray st aug before April and after September, and a strong pre-emergent program.

But if I had to spray in June, I've always thought Celsius (or was it Temacity?) was a little easier on St Aug as it was rated to 90 degrees as opppsed to 85


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## Ecks from Tex (Apr 26, 2018)

Greendoc said:


> Yes. One of my mentors, a golf super, warned me about what PGR can do to grass. It will reduce height and thicken it yes. That thickening can also translate to thatching. If it were me, I would PGR and fertilize the part of the lawn that needs work and keep the rest of the lawn on minimal Nitrogen and water.


Thanks man. I'm going to have to research PGR a little more as I've always had St Aug and therefore am a total noob with growth regulation; I've seen threads on here though that were very informative. I'll report back what results/effects I observe it my test plot.


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## Bunnysarefat (May 4, 2017)

I've sprayed MSM in summer with no ill effects. Of course, it's almost impossible to find a day that is cool enough in summer to spray. There just happened to be a day where the high was like 81 and the following day the high was about 85, then back to blazing hot after that, but I sprayed when it was 81 in a few spots and I saw no damage. SA has handled MSM very well in the 3 times I've used it on it. Must be weighed precisely with a scale as was mentioned.


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## Greendoc (Mar 24, 2018)

So have I. Imagine applying it to an acre of St Augustine the last year it got up to the low 90s in Hawaii. It was weighed to apply 0.5 oz per acre. You know what keeps me from totally destroying lawns. A sprayer that applies a set amount. That application got run through a boom that applied a gallon per 1000 sq ft.


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