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Discussion in 'Pesticide & Herbicide Application' started by VARMIT COMMISSION, Apr 29, 2008.


    VARMIT COMMISSION LawnSite Senior Member
    Posts: 547

    What's the minimum temp. you have used certainty to kill johnson grass and crabgrass in bermuda? And what is the highest temp. you have applied certainty to bermuda without injuring the bermuda?
  2. tremor

    tremor LawnSite Bronze Member
    Posts: 1,476

    Never used it on Bermuda but for Bluegrass we're entering the period now in Southern New England. But NOT on Ryegrass.

    Fall apps are often best AFTER a light frost here.
  3. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 9,064

    I have no minimum temperature here. It works much slower for me when it is cool, cloudy and under 80 in the daytime. But I have used Certainty on warm season grasses provided the lawn is well fertilized and on an irrigation system at 90+. No problems. Herbicide injury is most likely when turf is under water or nutritional stress.
  4. wrivers

    wrivers LawnSite Member
    Posts: 45

    I have never damaged turf at 95+ with Certainty, but I've never controlled crabgrass with it either, mostly becuase it doesn't control crabgrass at all. Maybe you meant nutsedge?

    VARMIT COMMISSION LawnSite Senior Member
    Posts: 547

    Yes I did mean to say nutsedge. Certainty as far as I know wont kill crabgrass. What I want is a johnson grass killer that wont hurt my bermuda and MSMA just wont do it for me. Only temporary. From what I have heard 75 degrees is the coolest temp. to use it to get control of johnson grass and it takes 3 apps. to get it.
  6. wrivers

    wrivers LawnSite Member
    Posts: 45

    I'd wait until you'll have at least 4 consecutive days in the 80s, then hit it with Certainty at 2.0 oz/ac and the MSMA together. That ought to put a wallop on it.
  7. RobHawkins

    RobHawkins LawnSite Member
    Posts: 52

    Where is the cheapest place to buy Certainty? I need to kill Dallisgrass. NCSU used it with MSMA and X-77 Spreader for a 98% final control in tall fescue. I have a yard full of Dallisgrass, but I can't find Certainty for less than $185 for a 1.25 oz. bottle.
  8. PHS

    PHS LawnSite Senior Member
    Posts: 724

    $185, wow! I was at Ewing Irrigation the other day and he told me $95. I've never used Certainty before but I also have it in my material cost spreadsheet as $94 from a while back when I was looking at it but for some reason I didn't enter the supplier.
  9. Hoots

    Hoots LawnSite Senior Member
    from DFW
    Posts: 327

    Generally the warmer the temps=quicker kill. Definitely the same thing on your nutsedge. If you still have poa, like most of us do, it works wonders on that too. Most people go on 85+ temps. In the winter when we get some poa, we spray with Monument or Certainty (close to the same products) but it can take 4 weeks to yellow if the temps are not up above at least 50 in our case.
  10. yardprospraying

    yardprospraying LawnSite Member
    Posts: 152

    Just spray with 2oz/ac. rate and add a good surfactant. No need for msma. I would also tell your customer to wait as long as possible before they mow after the application. I usually tell them to wait at least 24-48 hrs before they water, and then wait 7-10 before they mow for the johnsongrass. I have never burnt a lawn and have sprayed it in 85 deg. temps. It might take a little longer in cooler temps, but it will get the "johnson's".

    Certainty is a pre & post emergent, so once you get rid of whats up, you shouldn't have any more come up (as far as johnsongrass goes). On nutsedge, try to use as fine of a spray as possible, to contact more of the weed blade. If you are using the old chemlawn shower nozzle, you might not have very good results. We typically use a flat fan spray on our chemlawn guns to give better coverage. Since you have a new PG, you should be ok as long as it covers good. I can't say though heard a lot of good and bad about leaf coverage. We usually just spot treat with a backpack for the sedges though.

    Good luck,


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