Lawn weed killer browning/killing grass

Discussion in 'Pesticide & Herbicide Application' started by drugrep, Jun 19, 2009.

  1. drugrep

    drugrep LawnSite Member
    Messages: 44

    I'm spot spraying a quality brand of lawn weed killer. Main ingredients are:

    Monosodium acid

    I have mixed it very precisely.

    Why is it browning/killing grass where I spray?
  2. kirk1701

    kirk1701 LawnSite Gold Member
    Messages: 3,981

    What type of grass you have?

    My first thought is Fescue and if that be the case you might be overspraying the area. Add to that the amount of rain we've had might also be a factor.

    What's your mowing height?
  3. LushGreenLawn

    LushGreenLawn LawnSite Silver Member
    Messages: 2,120

    Is monosodium acid MSMA? If so you may have overapplied if you were spot spraying, or it may be a temporary browning of the grass which is normal. I am assuming based on fescue or bluegrass. We really need details to give sould advice. Grass type, tempature, and the trade name of the chemical would all help.
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  4. kirk1701

    kirk1701 LawnSite Gold Member
    Messages: 3,981

    Ahhh, missed that in my first read, yep MSMA would do it specially this time of the year.

    Its 88 here in KY today and drugrep is not to far north of me in Ill. I used to live in Illinois myself so I know the temps are brutal.
  5. drugrep

    drugrep LawnSite Member
    Messages: 44

    Northern lawn - Don't know exact variety, but sure combo of KBG, PRG, and TF.

    I mow at 3"

    In Chicago burbs, been rainy and cool. Only got hot within last couple of days.

    I do have a lot of fertilizer down, my Phosphorus is very low, so I'm using starter fertilizer year round. That comes with a lot of Nitrogen.

    Not getting the weeds as well as the grass.
  6. greendoctor

    greendoctor LawnSite Fanatic
    Messages: 10,124

    That weed killer you used is rebranded Trimec Plus. The guys that do cool season turf cannot give this product high marks. MSMA is really hard on cool season grasses. The strange thing is that it only works when it starts getting hot, but that is the time that turf tolerance is lowest. A hot day within a week of application is no good. BTW, what kind of weeds were you trying to kill? Cool season grasses are more tolerant of Acclaim or Drive if it is emerged crabgrass and most Three-Way herbicides if it is broadleaf weeds. But not a Trimec Plus type product. I can use it no problem on bermuda and zoysia lawns, but those grasses are not the same as a cool season blend in terms of herbicide tolerance. Spot spraying is something I do not do either. Lawns are broadcast sprayed at low to medium label rates. Spot spraying tends to overdose in the spot sprayed. Do not get me wrong, I have made lawns turn a little yellow with various herbicides. However it is easier to explain that than having the lawn look like a missile test site.
  7. lawn king

    lawn king LawnSite Silver Member
    Messages: 2,413

    MSMA is too damn hot, i wouldn't use it under any circumstances! Even if i was going to loose the client. Spray that product and the results will cost you the acct. anyway?
  8. Grandview

    Grandview LawnSite Gold Member
    from WI
    Messages: 3,251

    You are spraying too much. Broadleaf weed killers will burn lawns if applied heavy. You may have mixed it right but if your rate/area is high you can burn.
  9. JDUtah

    JDUtah LawnSite Silver Member
    from UT
    Messages: 2,636

    This guy knows his stuff... I'de back up this post. Because both who said it, and personal experience with what he said. :drinkup:
  10. Think Green

    Think Green LawnSite Silver Member
    Messages: 2,746

    I spray MSMA to control KBG--Fescue, then the heat will fry it out until fall...
    MSMA will yellow out the bermuda and zoysian in large doses, but in small doses according to label rates, the damage will be minimal in the south. The heat is the trick for the Arsenical chemicals..............!

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