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Question for Ric

Discussion in 'Pesticide & Herbicide Application' started by klsgc, Aug 21, 2011.

  1. klsgc

    klsgc LawnSite Senior Member
    Messages: 318

    Ric and possibly others who have messed with this:
    I am interested in spraying a low rate of gly on some lawns to slow down growth. I am in Michigan and the lawns that have a growth problem are 20%fescue, 50%rye, and 30% blue (approximately). I have a few questions about this.
    1. rate- I was thinking of .25oz/k to start and moving up from there but really I have no idea on a starting point. (using a 40ish%gly)
    2. I know you have done it on warm grasses, does anyone do it on cool grasses?
    3. How many times per year do you need to spray and how often would I be mowing for the cool season grasses. Is there certain times that I would get the most affect? ex: before or after seedheads are produced?
    4. Are there any other long term effects you have observed on the lawn like issues with color, thickness, or overall health. Or, would I have a problem with killing off annual blue, poa triv, and bentgrass accidently and leaving large bare areas there? (not that that would be such a bad thing).
    5. Any comparison to using Embark? I would use that, but it is horribly expensive.

    This interests me very much and I know it would others out there, so any information you have to help me get started is much appreciated.
  2. Ric

    Ric LawnSite Fanatic
    Messages: 11,969



    Yes I fool with Chemical mowing. As part of the Utility landscape I also clone Perennial Peanuts as a Ground cover for those difficult areas to mow like steep banks Etc. I have made my living doing Fine Yards but I have always had an interest in economic control of Utility Landscapes such as ROW and Industrial areas. I am looking for that Mower guy that wants to hook up and do Utility type mowing. However there is more to it than meets the eye.

    First most Glyphosate Labels will have Chemical mowing instructions. Normally they are in section 8 or 8 C. But those instruction don't explain half the story. The big issue is to have a Mono-stand of turf that the PGR (regardless of which one) Works the same on all species of plants. The idea is to have a uniform growth of the Turf area. Throw into that mix soil type and available plants that will grow in the area or that habitat and you can have a real problem. In my case a Calcareous sandy soil doesn't support Bahia. Bahia sod is laid on ROW just long enough for weeds to take over. Chemical mowing will not work on that turf because PGR are also Herbicides to most broad leaf weeds. However Bermuda will grow from seed in our High pH soil and can be Chemically mowed successfully. Bahia in Low pH soil can also be chemically mowed successfully. Glyphosate can be used on a Mixture of Bahia/Bermuda successfully.

    I don't know cool season Turf. But I use different PGR on each type of turf. But you have a learning curve ahead of you that might be bigger than you realize. Calibrating equipment and adjusting methods of application is a biggie. Here are some links to Big time Chemical Mowers use for Large contracts.



    I gave up on building a mower/sprayer comb like the Diamond or Brown. Therefore I use a separate step and Chemical mow Right after the mechanical mow. BUT Remember you can only get the large areas with Boom sprayers. You still have to hand spray edges etc.

    Back to my statement about Ground Covers. Plateau (If you can get it) can be sprayed Over the top of Perennial Peanuts as a selective weed control. There are Tree GPR that used in ROW that only stunt the tree on one side. So this is a totally different area than we normally talk about on LS.


  3. txgrassguy

    txgrassguy LawnSite Gold Member
    Messages: 3,083

    Ric as usual has great advice, but I'll chime in on glyosphate for C3 turf use.
    In one word unless you have great G.L. insurance - don't.

    The basic problem isn't so much differing turf types but growth characteristic making a very low rate < .5oz per 2 gallons of water per 1K feet applied extremely critical. Also, applying glyosphate through a low volume applicator < 2 gallons of water per 1F feet is difficult unless you add a stable non ionic surfactant that will work at the lower rate common to the stand on sprayers.

    Your timing is way off as you need to apply the glyosphate perhaps no later than one month into your growing season and not at the end. If you make an error now you'll be very hard pressed to renovate and get a sufficient stand prior to the on-set of dormancy. Remember any damage now to the host stand of turf will seriously affect the plants' ability to over winter without significant snow mold damage.

    Of course issues like climate, available irrigation or rainfall may to a certain extent aide in your renovation efforts but right now isn't the best time to apply glyosphate as a PGR on residential turf.

    A much safer alternative is the older PGR's on the market like Embark or Primo.
    Both work well, have established history of low toxicity and almost no off target side effects like an error with glyosphate will produce. Embark is much less expensive than Primo but doesn't last as long making accurate re-application critical for uniform results.

    If I were you and wanted to apply now I'd start a program of Embark verse the Primo. Then if you see satisfactory results next year after emergence and established growth I'd begin to apply glyosphate starting at no more than .25oz per 1kt feet of turf and watch carefully for signs of root pruning and crown degradation. A good time to apply is immediately after spring aerification and core clean up. This way if excessive turf loss has occurred the renovation effort will be much easier on you. Plus you can, to some extent, explain the turf loss as a result of mechanical damage verse an application error.
  4. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    BOTTOM LINE IS DON'T USE ON FINE TURF. Chemical Mowing is for Utility Turf where a yellow or Brown can be tolerated.

    I quickly found not all species don't react the same to PGR of any kind. Glyphosate works as a PGR by slowing down photosynthesis and starving the plant so it grows slower. Starve that plant by shutting down all Photosynthesis and you have a Herbicide instead of a PGR. Fact is Many PGRs are Herbicides used at a lower rate. I did look before posting to see Fescue was listed on several Glyphosate Labels. The standard Monsanto Label lists Chemical Mowing in section 8. However I found this label which seem to have just about every use of Glyphosate Listed. The bottom of page 23 and the top of page 24 list growth suppression rates and species.


    I will say I am at a real disadvantage trying to give advice on Cool Season turf. While I have studied Cool Season turf in college, my interest was only to pass the test and forget it.

    Not all C-4 turf react to Glyphosate the same. The rate that works perfect on Bahia will kill St Augustine slap dead. In fact 10 oz or less of Glyphosate per acre kills St A. Yet I have used 3 times that amount on Bermuda to have it laugh at me and come bouncing back after a dominant period caused by the Glyphosate. Primo rates on St Augustine are only 4.5 to 6.5 Oz, so it is very affordable. However on Bermuda the Rate is 33 Oz per acre and Bahia is 44 Oz per acre which takes Primo out of the affordable range. Plateau works wonderful on Bahia on acid soil. Suppression can last up to one year depending on tolerance levels. However remember My first post about Mono-Stands. Plateau is in fact a Herbicide use by Peanut farmers as a Over the Top Herbicide.

    Here is a Ric Secret. Because of how affordable Primo is on St Augustine, I use it all the time. But I don't cut grass so I am not interested in slowing Top Growth. Instead I am after the growth redirection to the Roots and Lateral growth. Primo will help St Augustine grow root extension fill in dead spots and makes the Turf thicker and more weed resistant.

    IMHO I Believe Chemical Mowing will come into it's own and those who are First to provide it in a Well thought out Business plan will make great money at it. While Glyphosate might not work on all C-3 turf as it doesn't on all C-4 turf, I am sure there will be other products that do.
  5. Aha. That is the answer I was looking for. Unfortunately I can't apply any of this stuff, but if I ever become licensed, I will start using that on St Aug. For the benefits you described.
    Posted via Mobile Device
  6. BShaffer

    BShaffer LawnSite Member
    Messages: 119


    I believe we have touched on this during our conversations, but do you see a noticable difference when using primo on St. Aug. At 5 oz/ ac are you going every 6 weeks?
  7. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    Heavy August Rains have played the devil on everything. I have had to tweek my blend real hard. While I cut back or Cut out a lot, the one thing I increased was the Primo. But this is Fine Turf and this time of year you have to cut it weekly no matter what.

    Two Points about PGR. 1st they work better the more they are used. 2nd there is a Spring Back or flush of growth when PGR wears off.
  8. BShaffer

    BShaffer LawnSite Member
    Messages: 119


    I have learned about the flush when primo wears off. on the bermuda fwys you think it might hold one more week and you take that chance and over the weekend the fwys release. you come in monday and you have to double cur those fwys to get them cleaned up!! not good.
  9. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    And the point here is not to break the cycle of PGR. Like I said above PGR work better the more they are used. But don't break the cycle or you start all over again. BTW if you watch Grass Grow, you will notice is also has a spring back from being mowed. After first being mowed it grows slow and then it booms. This is more noticeable during periods of Heavy rain because the grow change is more dramatic.

    As the old farmer told me years ago, ""The short you cut it the longer it lasts."" Trouble is you cut it too short and it lasts forever. Same with PGR, so be care not to over apply.
  10. txgrassguy

    txgrassguy LawnSite Gold Member
    Messages: 3,083

    Ric, I have a great deal of experience with PGR's on C3 turfgrass which is the basis for my earlier post.
    While I have not attempting C4 chemical mowing except on right of way areas I personally am quite hesitant to suggest using glyosphate on fine C3 turf which is why I suggested Embark over Primo.
    On critical issue with Primo that Embark doesn't have is off-target effect. Embark is much more forgiving when first experimenting especially with less skilled applicators.
    I will say on ultra low height of finished cuts like a putting green Primo is much more efficacious than Embark as correct timing will suppress Poa Annua seed head development allowing for extremely effective control of Poa in putting greens.
    I have always shook my head when alleged superintendents lamented they couldn't control the Poa on their bent greens and surrounds instead of intelligently applying Primo at the correct timing. Two years at one course and I eradicated all the Poa on the existent greens without resorting to expensive herbicides or re-seeding.
    Regarding the original post and comments I still say Embark is a much safer alternative than glyosphate or Primo.
    Of course, in the intervening time from my NE C3 experience a newer PGR may have made it to market but I always have Embark on hand as it is quite effective as an ornamental PGR on the estates I maintain. One day of application gives me almost four months of control which has significantly reduced my labor costs associated with landscape trimming.

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