Downsides to applying preemergent early

Discussion in 'Pesticide & Herbicide Application' started by nolo, Feb 10, 2018.

  1. nolo

    nolo LawnSite Member
    Messages: 93

    Are there any downsides to applying early? The University of Florida recommends applying early March for my area. It's been warm the last week and next week highs are going to be between 78 to 82. I'm thinking about just applying granule form preemergent for crabgrass next week.
     
  2. TPendagast

    TPendagast LawnSite Fanatic
    Male
    Messages: 13,392

    So there’s a “life” or longevity to the application

    Depending on the product you’re using and the weed season in your area, applying too early might see a waning of your protective barrier when the weed season isn’t over yet.

    This may not be an issue
    Or it might be
    Read the label and the calendar and possibly choose a different product with a higher persistence to get what you want.
     
    Fresh_Cut and hort101 like this.
  3. grass4gas

    grass4gas LawnSite Senior Member
    Messages: 673

    You can apply a heavy app with the hope it will last through the season, but with your sandy soil it may or may not leach out early. You also need to be concerned with having to seed in the fall making sure that the pre is out of the soil

    To be safe, I would do a split app. That is what lco’s around the beach areas of my state do. They are the closest soil conditions to yours that we have.

    Good luck
     
    RigglePLC likes this.
  4. Scagtastic

    Scagtastic LawnSite Member
    Messages: 155

    In the midwest we look at the Forsythia , when it begins to bloom its go time. We also do checks on soil temps when consistently 55 or above we go. We have had years where this happens earlier and yes the protective barrier that you are placing into the soil profile can break down if applied to soon. That being said what we have noticed on the clients yards that are consistent about lawn applications is that the yards stay much cleaner for longer periods of time, not to say they are immune to weed/crabgrass pressure, just that we have increased the threshold for encroachment to begin. Would also add that the homeowner plays a role in this process as well, our cover letter with the prepay contracts each year illustrates the importance of proper mowing, height, sharp blades, clean deck, etc. Have found that educating the clients helps make us look even better in regards to the end results.
     
  5. grassmasterswilson

    grassmasterswilson LawnSite Fanatic
    from nc
    Messages: 5,098

    Earlier is better. Depending on your location and soil temps.

    Pre is broken down my soil organisms so the products last much longer in colder weather when microbes are less active.

    I am in the transition zone and I’m already 4-5 days into round 1
     
  6. Digitaria Sanguinalis

    Digitaria Sanguinalis LawnSite Member
    Messages: 210

    Which Pre-m are you going to use? Photo degradation plays a much larger role than soil microbes in the break down of pre-emergents.
     
  7. TPendagast

    TPendagast LawnSite Fanatic
    Male
    Messages: 13,392

    Photo degradation is a bigger issue if the product hasn’t been activated

    Most of the granulars act that way, but if you water them in or it rains, then it’s going to do it’s thing according to label.

    Snapshots a bad one for sitting there inactivated, breaks down to near useless in sun fast.

    Also depends on your application surface and how much cover there is?
    Course gravel?
    Mulch?
    Bare soil?

    Then there’s ground disturbance, excessive rain/erosion... so many mitigating factors , it’s like trying to predict the weather for the whole season.
     
  8. Digitaria Sanguinalis

    Digitaria Sanguinalis LawnSite Member
    Messages: 210

    You left out plant uptake and volatilization
     
  9. Ijustwantausername

    Ijustwantausername LawnSite Bronze Member
    Messages: 1,812

    I am jealous man, I was hesitant to do it before this rain system as they were talking about flash flooding and 6+ inches of rain so I didn't want it to get washed away. Kicking myself now, especially since temps have really shot up for this week and next!

    Soil temps have shot up quickly too, they are already 56 here in Raleigh with this rain system.
     
  10. ltdlawn

    ltdlawn LawnSite Silver Member
    Messages: 2,237

    Forgive me if I'm wrong but doesn't the preM prevent not only the germination but also the emergence? Meaning seeds in ground that germinate would still be stopped at the barrier?
    All my research says soil temps of 55-60 consistently is what cause germination. I would assume consistently means 7-14 days to allow time For germination.
     

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