The stickies on the Cool Season Lawn Guide is a great source for your questions, members have taken time to write or answer common questions: PGR + Cool Season Grass

Now that I've been using it for 2 years, PGR is one of the things I wouldn't do lawn care without. I apply 0.35oz/K trinexapac every 2 weeks, and the benefits I've noticed are:

• Slows down growth and reduces the amount of mowing needed. When I do mow, there's far less clippings.
• Increases density,
• Significantly enhances color.
• Reduces seed heads
• Increases root mass
• Does wonders for me as far as drought resistance through the summer.

It's a jug of magic

 

I looked through this and saw some really good opinions — I’m looking for a blend of opinions and research. Most people on here have great lawns because they take care of it — their excellent mowing habits, Elite seed choice, proper fertilization, proper soil amendments, ideal irrigation etc etc could all explain away the benefits that PGR tends to get the shine for.
I’m not suggesting it does nothing I’ve seen through my Overseed that it gets work done — I’m just looking more towards what studies have shone. I’m buying it regardless I just want to know what’s real and what’sa myth you know?

 

I can say it definitely makes the grass darker (or at least prevents it from getting lighter during stress periods as it normally would)...no doubt in my mind about this one. It has done this every time, and I've used two different PGR AIs so far, over 8 years now (7 years with one, 1 year with the other). Both have done this.

It has also appeared to help reduce irrigation demand slightly.

One not on your list that I think I've seen: Possibly increased nutrient longevity between fertilizer apps, as well (evidenced by stronger growth for longer). By stronger growth, I mean how vigorously it grows...not how fast. It slows the growth rate, but I get the feeling that overall consistency and vigor of growth response after fertilizer is increased by PGRs. Hard to explain. But normally fertilizer increases growth for a while and then slows. During consistent PGR suppression, growth seems more consistent and strong over time after fertilizer apps...better growth and without the peaks and valleys in rate.

I'm not totally sure about thickness. I think it has made the grass thicker at times. But I can't really prove it. And I'm not sure if that's due to thicker individual blades, higher blade density, or both.

Lateral spread, I'm not sure if I've seen any enhancement in. Maybe. Maybe not. No idea...it's not any worse, though.

However, the biggest difference I've seen is reduced mowing...mowing every 3 days on untreated areas versus every 5 or so on treated during August 2023 in my case. This is the biggest benefit.

 

Google Bill Kreisler as he has done on a studies and trials. He is the leading authority on PGRs in my opinion.

 

Bill Kreuser

 

Hey guys, I’m prepping myself for next season and PGRS really seem like a winner and will be something that I should invest in. — I used it for my Overseed and boy did it do its job.

But as much as I’ve looked into this product — and where the consensus is overwhelmingly Suggesting it’s a winner — I still want to know what it’s bringing to the table so that I can purchase around the product accordingly. My questions for the veterans if this forum and for the PGR guys is:

1: what has your experience been with it making your grass DENSER, and what does the science state about this?

2:what has your experience been with it making your grass SPREAD LATERALLY, and what does the science state about this?

3: what has your experience been with it making your grass APPEAR DARKER, and what does the science state about this?

I’ve got the TNex queued up on domyown and the willpower of a four year old in a candy shop, lay it on me lol

1: Pgr has been shown to promote tillering which would make the turf appear denser.

2: While there is some benefits to low rate pgrs promoting lateral growth, it will not be substantially different than if no pgr was used. As you go higher and higher with rates the plant will become more and more regulated. Any pgr applied at high enough rates can stop all growth, lateral included. This varies greatly from pgr to pgr and the one pgr that can substantially do this (paclo) is not available to the residential market.

3: Grass will be darker with any pgr due to the cells being smaller and still containing the same amount of chloroplasts. Think of 10 people in the room your in right now and then shrink that room by 15-65%.

 

Tried them on both zoysia and Bermuda turned it all orange/green at low rates looked horrible. Scrapped that idea.

 

1000's of golf courses in the south and Midwest apply pgr's on Zoysia and Bermuda just fine. Application timing, use rate, product, or applicator is the cause of the bronzing.

 

I’m sure it is.

 

When did you apply, what was the temperatures (lows primarily), what product and rate was used?

 

If I also cut the lawn every single day or at least every other day the bronzing problem wouldn’t occur. But that’s what you get with cultural methods of residential lawn care.

 

One of the guys who worked on R&D for Primo or Primo Maxx (works at Syngenta as a technical rep now, forgot his name but could look it up) said he feels bronzing is due to overregulation causing slow turnover of senescing leaf blades.

I saw some long-term browning with medium rate Anuew on very high areas over 4 in that I don't trim often, but no worse than what minor drought would do.

@Supergrass , I saw another article mentioning the Poa suppression from Anuew. They acknowledge it's not "bite you in the head" in terms of intensity (my words), but that it's definitely there:

"...Cutless MEC tank-mixed with Anuew has become a popular option. The Cutless application rate drives the amount of Poa annua suppression (while adding some turf growth suppression) and the Anuew application rate drives the desired turf growth suppression (while adding some Poa annua suppression)."
Link to source article quoted: StackPath

 

Bronzing/Over regulation occurs due to to much a.i. being in the plant. More than the plant can metabolize. Plant metabolizes a lot when its hot and not as much when its cool. In turn much easier to see bronzing when it's cool.

I was speaking with a PhD over last couple of days. He did believe that a plant does have to be conditioned to a pgr. In green house trials with constant temperature, turf would bronze at medium rates but the following application they would not.

And yes Anuew does have a tiny bit more poa suppression than primo, in turn it is better to mix cutless with Anuew. There has also been a synergistic activity from the research I have seen on it.

 

Bronzing/Over regulation occurs due to to much a.i. being in the plant. More than the plant can metabolize. Plant metabolizes a lot when its hot and not as much when its cool. In turn much easier to see bronzing when it's cool.

I was speaking with a PhD over last couple of days. He did believe that a plant does have to be conditioned to a pgr. In green house trials with constant temperature, turf would bronze at medium rates but the following application they would not.

And yes Anuew does have a tiny bit more poa suppression than primo, in turn it is better to mix cutless with Anuew. There has also been a synergistic activity from the research I have seen on it.

Good info.

And what you described is basically synonymous with overregulation...no?

And I'd argue Anuew is more than a "tiny bit" different, in my limited use of it so far, when it comes to Triv. Although I see some Triv popping back up now, it still feels like less than typically comes back this time of year. We will see how it goes after my recent app, but my guess is that the suppression from Anuew only really works in Spring and Summer, not so much in late Summer and Fall. That seems to be the pattern so far, anyway. I think it probably has something to do with seed formation and maybe day length if I were going to guess.

Maybe Anuew plus Cutless will prove to be the best PGR combo for Poa suppression in residential lawns, based on the synergy you mention.

 

Just keep waiting for the Purdue study to come out. It is on poa annua but Anuew is not statistically different than primo. I little more but not much.

 

Just keep waiting for the Purdue study to come out. It is on poa annua but Anuew is not statistically different than primo. I little more but not much.

Ok. I'm sure you'll see it first when it comes out, and will probably let me know.

I don't remember seeing any Triv suppression from Trinexapac-ethyl, at all, in like 7 years of use on the same lawn.

But one year with Anuew, I saw something notable.

Of course, annua isn't Triv, either. And there are so many types of each, and then lawn or golf or sports fields differing, regions, etc...

 

Ok. I'm sure you'll see it first when it comes out, and will probably let me know.

I don't remember seeing any Triv suppression from Trinexapac-ethyl, at all, in like 7 years of use on the same lawn.

Of course, annua isn't Triv, either. And there are so many types of each, and tyen lawn or golf or sports fields differing, etc...

I have seen it. They are continuing this year with the trial as well and adding paclo to the mix. What was your rate of primo and your current rate of Anuew.

 

I have seen it. They are continuing this year with the trial as well and adding paclo to the mix. What was your rate of primo and your current rate of Anuew.

Anuew, I have used as low as 0.06 oz/M (in conjunction with other things that regulate growth, like Velocity or Propiconazole), up to 0.26 or 0.28 oz used alone. I've only used max label rate (0.37 oz) before overseeding. Typically most used rate for me is like 0.18 to 0.2. Also did some ~full rate test spots.

I will look up my Primo rates and edit this post to add them here.

 

Anuew, I have used as low as 0.06 oz/M (in conjunction with other things that regulate growth, like Velocity or Propiconazole), up to 0.26 or 0.28 oz. I've only used max label rate (0.37 oz) before overseeding. Typically 0.18 to 0.2.

I will look up my Primo rates and edit this post to add them here.

Velocity applied to the triv as well?

 

Velocity applied to the triv as well?

One area got three blanket apps of Velocity at 2oz per acre this year, as well as the 7 or so apps of Anuew. Even with both having been used, there is still Triv popping back up in a few spots this month. This same area is getting Mesotrione this week. So will the Anuew-only area be getting Mesotrione. I hate to confound things, but I need the Mesotrione to zap any early Poa annua that may have popped up...haven't gotten the real pre-M down yet.

My most used rate range of Trinexapac-ethyl last year was 0.2-0.3 oz/M (versus 0.18-0.22 for Anuew).

 

Have you experienced a rebound with either? I know from the studies I’ve seen bc anuew “is like every other PGR only more so “ meaning it’s suppression really suppresses but it’s rebound really really rebounds.

also I wasn’t really about to find information on the relationship between PGRs and meaningful amounts of Nitrogen (more than .25N per k). I am really interested in know what happens when the plants GA is being instructed to minimize cell elongation and upward growth while simultaneously being fed nutrients which it utilizes for growth

 

I've always seen some rebound when overseeding, because it was only one application.

 

@Supergrass

I had no idea that some golf courses (cool season I guess) are using under 1 lb of N per year, total. What is this on (fairway?). And does the short mowing height have anything to do with it? Or the grass species used?

I would have thought most courses would have been using 1.5 to 4 lbs per year. This just shows I know nothing about golf (golf turf or the game itself).

 

This is cool season turf and depends greatly on the course and desired goals. Greens are usually on the lower side. Most feed with around 0.10# N/ 1000 sq ft bi-weekly and lay off N during the summer due to the amount of mineralization that is taking place and to not promote disease. This is done for different reasons than a lawn where the main goal is to have it green. While most courses do look great doing this, it is done for more of a labor savings (less clippings to blow/remove) and playability standpoint. Low N=finer leaf blades=more ball roll.

 

In my opinion, the biggest difference will be you being able to, if you want, or need to, go an extra day, two days, or three days between mowing. You can still mow just as often, if you want. You won't take off as much. There is a point when it makes no sense to mow, though. You'll just be dulling your blade and using up energy/causing pollution without much gain. (And I'm someone who has mowed twice a week sometimes only to take off a centimeter or so from a 3 or 4 inch lawn at times.) since you plan to reel mow, you'll probably be mowing twice a week, PGR or not. But you could maybe go an extra day or two at times with it.

 

The one year I tried it I ran it at 1/4 max rate and got bronzing out the yin Yang but I was applying to lawns that get cut every other week. Trying (at the time) to give my lawn mow guys a little break. Just didn’t work for me. Just my buck fifty nothing more or less. Tiff 2 almost exclusively.

 

Bermuda can be difficult sometimes with primo. If you made a second app I would almost guarantee the bronzing wouldn't have occurred with the second app. Secondly with Bermuda, if nighttime temps are dropping low you will seed bronzing (below 60 degrees). Lastly, you do realize your in the cool season section of the forums?

 

No I did not sorry!!!

 

Again so sorry been trying to stay in my lane since joining somehow I missed this one. I do really like how it is divided up between warm and cool season just had the brain fart on this early on. My apologies.

 

Haha! Not that big of a deal my man! I was just checking.

 

Bermuda can be difficult sometimes with primo. If you made a second app I would almost guarantee the bronzing wouldn't have occurred with the second app. Secondly with Bermuda, if nighttime temps are dropping low you will seed bronzing (below 60 degrees). Lastly, you do realize your in the cool season section of the forums?

@PickleRick

Greendoc starts at or below 0.10 oz per thousand on some types of Bermuda. He is the expert on that, so you may want to ask him.

 

@Green and I have different goals which means our rates/product/intervals are different.

What are your main goals for using PGR on your lawn? My main one is to avoid mowing every two to three days, and to increase the resistance to Summer stress at the same time...but without slowing down growth too much. Mission accomplished. I didn't water much this year, and went longer between irrigations during periods with no rain, versus other years. Everyone else around here except for a few watered more than I did. Partly from the PGR, partly from withholding irrigation in early Spring and pre-conditioning it (long story that began in late Winter due to too much rain--a foot and a half in a couple months--causing root die-off over late Fall and continuing into Winter, and therefore extremely sluggish Spring greenup...and it then became a game to grow the roots back and therefore water as little as possible until late July, pushing the limits). Because the greenup was so slow, I was not mowing until well into April and May depending on the area, and did not need to apply any PGR until much later than usual (first week of May for the front, and not until July or August for the back). Now, 7 applications later (front) and 2 in the back, and I'm very pleased with the results.
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This is cool season turf and depends greatly on the course and desired goals. Greens are usually on the lower side. Most feed with around 0.10# N/ 1000 sq ft bi-weekly and lay off N during the summer due to the amount of mineralization that is taking place and to not promote disease. This is done for different reasons than a lawn where the main goal is to have it green. While most courses do look great doing this, it is done for more of a labor savings (less clippings to blow/remove) and playability standpoint. Low N=finer leaf blades=more ball roll.

Interesting. Makes sense. How the heck did you uniformly apply granular N at 0.10 lb rate...let alone to a small, odd-shaped area whose boundaries are weird and area is hard to accurately calculate? And also not overshoot the edge? Using the Andersons spreader?? Even with like a 15% N greens grade product I would think that would be tricky. Or were you spraying?

I've been doing much lower rate granular apps than this in 2023, but it's on larger, regular lawn areas with 8% N products.

 

What are your main goals for using PGR on your lawn? My main one is to avoid mowing every two to three days, and to increase the resistance to Summer stress at the same time...but without slowing down growth too much. Mission accomplished. I didn't water much this year, and went longer between irrigations during periods with no rain, versus other years. Everyone else around here except for a few watered more than I did. Partly from the PGR, partly from withholding irrigation in early Spring and pre-conditioning it (long story that began in late Winter due to too much rain--a foot and a half in a couple months--causing root die-off over late Fall and continuing into Winter, and therefore extremely sluggish Spring greenup...and it then became a game to grow the roots back and therefore water as little as possible until late July, pushing the limits). Because the greenup was so slow, I was not mowing until well into April and May depending on the area, and did not need to apply any PGR until much later than usual (first week of May for the front, and not until July or August for the back). Now, 7 applications later (front) and 2 in the back, and I'm very pleased with the results.
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Interesting. Makes sense. How the heck did you uniformly apply granular N at 0.10 lb rate...let alone to a small, odd-shaped area whose boundaries are weird and area is hard to accurately calculate? And also not overshoot the edge? Using the Andersons spreader?? Even with like a 15% N greens grade product I would think that would be tricky. Or were you spraying?

I've been doing much lower rate granular apps than this in 2023, but it's on larger, regular lawn areas with 8% N products.

My goal is darn near complete and total shutdown of the plant (mow once a week). While Kreuser has conducted the one study that showed on tttf that brown patch is more prevalent on slow growing grass, I personally am not going to base my pgr program on that. That might change if I see issues in the future, but I had no problems this last year and will continue to do so until I do see a problem with less than an 1" of growth in a week. Also find it funny that he would refer to a length of growth (1" of growth for 3" turf is completely different than 1.5" turf). In my personal opinion, typical Kreuser research that pushes a narrative to get views/ recognition without intensive repeated research. Again, this is personal preference and there is "research" (if you would like to call it that) that showed low growth promotes more brown patch on tttf.

0.10#'s N were applied foliar through soluble fert or the con-artist water in a jug with little nutrients. While there was some overlap into surrounds on greens, tees, and fairways it was very minimal. This is why lots of superintendents are moving to gps sprayers with individual nozzle control (most have 2" accuracy). Pesticide on target every time.

These rates were highly dependent on sub soil as a usga spec green leaches more readily than a push up, so more N could be needed. Also an ENR on their soil report was also heavily leaned on for calculating how much N was needed versus what could be released.

 

@Supergrass

Cool. No idea how those GPS sprayers look or work. We can discuss another time.

But real quick since you mentioned it and not to deviate from topic...any reason to pay for ENR on a soil test, or is it just something I could calculate myself from the results? I was actually wondering this for months now. I want to know as I seem to have major N mineralization these days. And I had to up PGR rate due to it in July and August. I'd up the rate each time, but it was like chasing a moving target still.

Btw, I found Anuew is apparently not at all linear in terms of rate versus suppression level. There is not a huge difference necessarily (not as big as I would have thought) between 8oz per acre (0.18oz per thousand) and max or near max rates. I think T-Nex may have a more linear response from memory. I did two stacked apps of Anuew that together added to somewhere in the upper third of the rate range, prior to an overseed a couple weeks ago. Now, the grass is higher than I would have expected and needs a mow. I feel like 0.18 to 0.28 oz or so gives the best bang for the buck.

Ever heard of anyone going above label rate range for Anuew? Or T-Nex? I've heard of it for T-Nex. Guessing you've done it (with your "Nuke rates", lol).

 

If you know your soil type and your SOM you can estimate your ENR.

I have seen this curve with Anuew. Very interesting that lower rates provide decent suppression compared to high rates. Where I think this plays well is spraying lower rates of Anuew to keep costs down and then spiking with primo if growth suppression is the only goal.

I have heard of people spraying above label rates. Not legal per the label but many people do it. Again, boils down to your goals and what you deem acceptable.

 

If you know your soil type and your SOM you can estimate your ENR.

I have seen this curve with Anuew. Very interesting that lower rates provide decent suppression compared to high rates. Where I think this plays well is spraying lower rates of Anuew to keep costs down and then spiking with primo if growth suppression is the only goal.

I have heard of people spraying above label rates. Not legal per the label but many people do it. Again, boils down to your goals and what you deem acceptable.

Thanks for confirming the rate thing with Anuew. This is exactly what I felt...it can be a waste of $ to spray rates above a certain level. I feel like everyone should start at 0.18oz (or possibly even a little lower) with Anuew. Increasing that by 50% is useful, but doesn't seem to yield another 50% increase in growth suppression...more like, I don't know...20%. I'm not impressed by roughly max label rate on my test areas.

I know Primo Maxx allows up to, I think it said 2oz per thousand or something...but not to exceed 7oz total per year...if I remember correctly. They used to to claim increased duration by doing this back in the day (1990s) with original Primo. (Yes, I went and dug up some old labels on the EPA site.) Of course now we know that any increased duration is nowhere near what they claimed with the way the curves work. I'm not sure if the current label has this 2oz thing on it.

What does SOM stand for?

 

Soil organic matter

 

Is aneuw worth the money? Or is a jug of TNex the best most practical bet

I bought Anuew to use this year because it supposedly lasted a bit longer (really several days, not a major difference), seemed more cost effective at low to medium rates (it can be, but again not a huge difference)...it's a solid (so I think it might keep better...but now they also have a liquid version, too). Suppisedly softer rebound (but growth suppression is also softer as rates increase). And because people reported plant suppression effects on Poa Trivialis, which I deal with (it does seem to have helped suppress it during the Summer heat, but jury is still out as to how much of a sustained effect it has as we move into Fall). And since I started using it, I also learned that Anuew activates faster. Whether this results in faster onset of action, I'm not sure. Maybe one day faster, at the most. And I learned it's more active at lower rates. The advantages of Anuew are there, but are minimal to moderate.

Advantages of Trinexapac over Anuew that I've found:

-proven over time on turf. Many studies and users

-costs less for a gallon of generic like T-Nex or Pramaxis, but you may need higher rates which may offset this. Generic Anuew is a little less expensive than the name brand. Generic Trinexapac is significantly less than even Syngenta's own generic (Podium).

-increasing the rate lowers growth predictably (more linear). My impression is that I think max rate probably reduces growth more than Anuew at max rate.

-and you can control very low rates better with Trinexapac-ethyl as well.

-very pronounced blue-green darkening effect at medium to high rates (Anuew does it too, but it's slightly less blue or more subtle somehow).

-it's a liquid. Some prefer that.

-no problem tank mixing with a wide variety of things without having to test first, is not finicky about hard water (Calcium) like Anuew is, and does not require adding in a surfactant (Anuew strongly recommends one). You never know what has calcium or a similar incompatible ion in it. I think twice about mixing products now with Anuew. And I always use distilled water with Anuew.
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I consider a PGR essential. Without, I'm mowing up to 2-3x per week. With one, I'm mowing 1-2x per week. Either one achieves this.