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Herbicide applications with dew on the ground

Discussion in 'Pesticide & Herbicide Application' started by jeasley, Oct 15, 2010.

  1. jeasley

    jeasley LawnSite Member
    Messages: 49


    I did a search, and can't find much info. What are your thoughts about spraying herbicides (post or pre) while there is a dew on the ground. As our days are getting shorter and shorter, it is hard to get a full day in, if you have to wait for the dew to dry. I have read some research that said with a post application, a dew MAY improve efficacy, assuming that your applied material stays on the leaf with the dew, and does not roll off to the soil. I don't know if I buy that myself though.

    I predominately am interested in PRE's though, as that's what I REALLY want to start spraying at daylight tomorrow.


    Jake :usflag:
  2. ted putnam

    ted putnam LawnSite Platinum Member
    Messages: 4,717

    First of all, I don't begin spraying at daylight unless they are commercial accounts. I'm on my first lawn close to 8am. Kids are at school and adults are gone to work by then. Less chance of unecessary confrontation with an otherwise problem free customer.
    When there is dew on the turf/weeds, the pores of the plant ar actually more open to accept moisture into the plant. For this reason, you actually get some excellent weed control because along with the moisture making easier entry , the herbicide does as well. I've never had a problem with it but if you have a hard time accepting this, add a little sticker to the mix. You'll still get great weed control and you'll have added a little "peace of mind" to the mix as well. JMO
  3. jeasley

    jeasley LawnSite Member
    Messages: 49

    I will buy that, sounds good to me. I have alot of larger commercial type lots so I can start at daylight there. However, putting out pre's that are not taken in by the plants, (active in the soil), I wonder how the dew will affect them? Best case scenario is to get a rain shortly after the application. In fact I have applied them in the rain before with great results......just wonder how the dew will impact it? Think I will try it, Simazine is pretty cheap, lets see what happens.......

    Thanks Ted!!
  4. grassmasterswilson

    grassmasterswilson LawnSite Platinum Member
    from nc
    Messages: 4,968

    doesn't matter with pre......they bind with the soil and not the plant.
  5. grassman177

    grassman177 LawnSite Fanatic
    Messages: 9,795

    wow, really
  6. greendoctor

    greendoctor LawnSite Fanatic
    Messages: 9,999

    Under the right circumstances, simazine is absorbed by leaves as well. The key to making it all work is as much water as possible short of what makes it run off site or wash past the root zone. You do know that simazine should be irrigated in or have rain within 10 days. For post emergent herbicides, I am always using the appropriate surfactant for the product. I literally have three different surfactant/additives for different products. Dew or water on the grass does not affect things.

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