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Overseeding after Pre-M has been applied???

Discussion in 'Pesticide & Herbicide Application' started by CutNLawns, Mar 17, 2008.

  1. CutNLawns

    CutNLawns LawnSite Member
    Messages: 184

    Have to ask but a mowing customer has asked me to aerate and overseed his lawn next week and I noticed that the lawn was just sprayed last week with a prodiamine Pre-M application by another outfit. I am new to this chemical stuff so I have no problem asking if i am unsure. It has rained quite a bit since the application but have been told it is OK to seed and also not OK to seed. What is your opinions or past experiences? Thanks!
  2. mnturfmaster

    mnturfmaster LawnSite Member
    Messages: 65

    If prodiamine was applied, you will not be able to seed for 4-6 months, depending on the rate that it is applied. The grass seeds will not germinate. Also, aerating after pre-emergent will open up voids for the crabgrass to germinate. The only pre-emergent material that can be used at the time of seeding is tupersan (siduron).
  3. vegomatic40

    vegomatic40 LawnSite Senior Member
    from 6
    Messages: 406

    Oh it's Ok alright. As long as you are ok with practically no germination. It's pretty unlikely that the turf would survive the summers you have in St. Louis area anyway (I'm assuming you are seeding with Fescue). Read the label on Prodiamine and seed in the FALL.
  4. grassman177

    grassman177 LawnSite Fanatic
    Messages: 9,795

    from experience i know you should tell him no, wait till fall. the aeration will reduce the effectiveness of the pre -m AND it most definitely will kill the seed. i put it down too strong last year on a few accidentally including my own and i could not get seed to grow at all with three tries last fall on my own. explain this to him and sign him up for fall.
  5. CutNLawns

    CutNLawns LawnSite Member
    Messages: 184

    This is exactly what I knew was the right answer but when a couple suppliers are telling you there should be no problem they made me start second guessing myself. Thanks for the input guys!
  6. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,559

    Sometimes my customers will seed after one of my pre-emergent applications. Sometimes it works fine. Try to get an idea of how much was per acre applied if the other company gave the customer full information as required in some states.

    You could try this. Dig up a 1 sqft sample of the turf. Take it inside where it is warm, put it in a bright window and seed it with the seed in question, (prepareing the soil the same). Ryegrass has very strong seedling vigor. I suspect it would have adequate germination. Bluegrass probably not, TTTF, probably not. Anyway you will know in about 10 days.
  7. GreenCare Consulting

    GreenCare Consulting LawnSite Member
    Messages: 53

    It also depends on what type of seeding that you are doing. If it is an aeration and overseeding versus slit versus whatever else you might try.

    My experience is that with a good aeration and overseeding, even with the pre, you will get some germination, but i agree with the fall seeding recommendations above for several reasons. First fall seeded turf is much more durable, more bang for the customers buck, and doesn't experience summer heat and compeition from crabgrass as a three month old plant.

    Also, if you aerate and overseed now, you will break the pre-emergent barrier and you will have crabgrass sooner than if you left it alone. This alone is not so bad, but the crabgrass will then outcompete the newly seeded fescue, and then in the fall you will find yourself out there again, performing an aeration and overseeding and asking for more money, which the client may not like as well.

    However, all that said, I would explain both options to the client and make a recommendation, and if he still says go this spring, then I go.

    Best of luck, GC
  8. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,559

    It is tricky--but potentially you could slit seed through the chemical barrier. And wait for seed to come up. AND THEN...apply crabgrass control. The timing is very tight.

    Or...do the slit seeding and control crabgrass with Drive.
  9. Frank Fescue

    Frank Fescue LawnSite Senior Member
    Messages: 713

    tell the customer that theres not enough product applied, ask to see the invoice left by the fert company to double check what product was applied, make note of the account #. tell him its ok to aerate and overseed as long as they dont do fert again. note the timeline between apps. then call the fert company up and demand they retreat the lawn tomorrow or you will cancel. give them the account #. when they come out and re-fert you should have a new customer.
  10. LwnMnWoody

    LwnMnWoody LawnSite Member
    Messages: 17

    Wait on it and reseed in the fall. That's the best practice here in VA.

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