pre-emergents and overseeding?

Discussion in 'Pesticide & Herbicide Application' started by sulston, May 2, 2007.

  1. sulston

    sulston LawnSite Member
    Messages: 52

    Hi, I'm in need of some info from someone who has experience with herbicides. I have a customer whom I was planning on overseeding their lawn in the next couple days, and thought just to be sure I'd make sure their lawn hasn't been sprayed with any kind of pre-emergent because I have read everywhere that grass seed will not germinate if a pre emerg has been applied, and you must wait anywhere from 6 weeks to 3-4 months before or after it is applied. So of course we found out it had been sprayed with a pre-emergent crabgrass control and I discussed my concern with the customer, she called the weed company and they told her that if you were to put down the seed before the pre-emerg was applied than you have to wait 6 weeks but since the pre emerg was already applied(3 days ago) you only have to wait one week to plant seed. I don't know too much about herbicides but everything I read goes against what this weed company has said. I would sincerely appreciate any info or advice from someone with the knowledge to clarify this for me. Thanks.
  2. Turfdoctor1

    Turfdoctor1 LawnSite Senior Member
    Messages: 707

    i'm guessing that your customer misunderstood what the weed company was trying to tell her. If you seed now and actually get the seed into the existing soil, your seed is not going to come up. That is the definition of what a pre-emergent herbicide does.
  3. sulston

    sulston LawnSite Member
    Messages: 52

    This is what I thought, so I decided to make a few calls to local weed companies so I could hear it from the horses mouth. I called four of the most commonly seen companies in my area and three of the four said without hesitation 8 weeks absolutely no sooner. I checked the product label for dimension which is what was applied and it even reccommends waiting for 3 months. The crazy thing is that 1 of the companies told me the exact same thing that my customer said she was told, if the seed has already been put down then you must wait 6 weeks but if not you can put seed down within 3 days but you might want to wait a full week to be sure. The even crazier thing is that this isn't even the company she has spraying her weeds, when I called that same company they said to wait 8 weeks. I just can't understand how a company that specializes in herbicides could give out information that is so far off, there's a huge difference between 3 days-week and 8 weeks-3 months. Strange but anyway I won't be putting down any seed.
  4. Nathan Robinson

    Nathan Robinson LawnSite Senior Member
    from 47712
    Messages: 317

    Why does she want seed to be planted now? It will not concentrate on storage. It will only concentrate on growth and respiration leaving this turf with no storage for the winter and spring to come. Explain that to her and maybe she will wait for the better results.
  5. garydale

    garydale LawnSite Senior Member
    Messages: 813

    Does your brain hurt when you respond on this forum. Because mine does when I read your comments.
  6. magland

    magland LawnSite Member
    Messages: 68

    I guess that company's pre-emergent only lasts 1 week. What would be the point then? I would say 6 weeeks either way with the seed, unless the pre-emergent is a higher rate of Barricade or Dimension. Then you should wait even longer.
  7. tremor

    tremor LawnSite Bronze Member
    Messages: 1,476

    I have a lot of customers that seed Perennial Ryegrass right into Dimension. No problems. It's "off label" but it works.
  8. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,814

    Good pint Tremor,
    I have seen customers seed ryegrass after a preemergent like Team was applied. The seed came up fine.

    Maybe a heavy raking to disturb the soil barriar would also help. Try it and let us know what happens.
  9. Runner

    Runner LawnSite Fanatic
    Messages: 13,497

    I am thinking that as long as the pre-em is dissolved into the soil, and it is then worked up enough to disrupt the barrier, the hindrance on the germination rate would be limited.
  10. Victor

    Victor LawnSite Bronze Member
    Messages: 1,430

    As always Steve, great information to know. I had no idea that would work. That could prove to be very useful information.

Share This Page