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Herbicide in cold

Discussion in 'Pesticide & Herbicide Application' started by RigglePLC, Apr 3, 2019.

  1. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 17,000

    So far I sprayed bittercress on April first with Speedzone or a 3-way (thermometer included in picture). At 48 hours the results seem to be rather slow. The temperatures have been about 55 as daily highs during this time; about 40 at night.




    dishman89 and Atlantic Lawn like this.
  2. J Hisch

    J Hisch LawnSite Bronze Member
    Messages: 1,049

    As you are aware up take is slower in cooler temperatures. Plus they are almost beginning to reach seed stage as I am seeing the white flowers which will also slow up take sense the weed has almost reached maturity. If it'sighly valuable turf or flower beds I would recommend Cool Power but it is expensive. But again on highly valuable turf it may call for it. You might also use a late fall BL application.
  3. OP

    RigglePLC LawnSite Fanatic
    Messages: 17,000

    At day three--there is still not much response. Sprayed with Speedzone; 49 degrees F at the time. Still rather cold the temp is 45 F today.
    I am not sure if bittercress is more resistant to herbicides.
    I think I can see some slight curling of the leaf blades.

    dishman89 likes this.
  4. weeze

    weeze LawnSite Fanatic
    Messages: 17,396

    doesn't do so well in colder weather.
  5. CorgiTurf

    CorgiTurf LawnSite Senior Member
    Messages: 636

    What rates per thousand did you go at?

    Any surfactants?
  6. OP

    RigglePLC LawnSite Fanatic
    Messages: 17,000

    The three way included surfactant.
    It is difficult to be precise with my equipment and method.
    I tried to spray about a half sqft (9.6 inch circle). Applied one squirt with trigger-spray--about 1 milliliter. That is about 2 milliliters per sqft, or 2 liters per thousand sqft.
    Herbicides were mixed at one ounce per quart.
  7. PKLIP

    PKLIP LawnSite Senior Member
    Messages: 281

    I have been spraying Cool Power with surfactant at the max rate. The temps here have been in the 50's to 60's, however nightime temps have been dropping into the 20's and 30's. The properties I sprayed last week of March have shown little effect, but I am guessing that in the next several days as temperatures warm up they will start showing injury.
  8. Atlantic Lawn

    Atlantic Lawn LawnSite Bronze Member
    Male, from Outer Banks NC
    Messages: 1,024

    Thanks for another real world herbicide test. Many LawnSite readers have no clue of your many years of real life herbicide experiments. You sir are the King of online weed killing. Keep it up.
    hort101 and gbobcatr like this.
  9. OP

    RigglePLC LawnSite Fanatic
    Messages: 17,000

    Thanks for your comments, Steve.
    Here are the new pictures of bittercress, sprayed with a 3-way, after 5 days.
    Then of an unfamiliar perennial weed with Speedzone. Sprayed at a temperature of 49 or 50.
    Temperatures dropped to about 38 F during the night.
    Response has been slow. Temperature is rising today--may hit 70. More results later.
    First mowing in our area will be about 3 to 4 weeks later.


    Last edited: Apr 6, 2019
    SFL likes this.
  10. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Messages: 10,793

    Our lawns here are JUST starting to break dormancy. Same with any residual broadleafs. Too early to apply selective yet.

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