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Crabgrass Control/Aeration

Discussion in 'Pesticide & Herbicide Application' started by Teach123, Mar 22, 2011.

  1. Teach123

    Teach123 LawnSite Member
    Posts: 155

    I have heard conflicting advice on the following question.

    "Can you aerate after crabgrass prevention has been applied?"

    Some say that aerating will break the "barrier" the product creates in the soil.

    Others say that research shows that aeration after application has no effect on the effectiveness of the crabgrass preventer.

    My dilemma: My lawn care guru applied Halts earlier this week before my scheduled aeration later this week. It is raining currently and the Halts is soaking in. If I aerate later this week, will it mess with the Halts? The way I look at it, the Halts hasn;t had time to make a barrier yet and the cores that are pulled will get reabsorbed back into the turf with Halts already in them. Any advice? I hate to reapply since I don't want to over do it and harm my gorgeous KBG.

    Thanks in advance for any advice!!!
  2. humble1

    humble1 LawnSite Silver Member
    from MA
    Posts: 2,499

    1) he is not a guru if he is using scotts plus halts, i bet he isnt licensed.

    2)aeration will most certaainly break the barrier so will dethatching it. I would wait until after the ground dries at least 1 week, dethatch it, mow it short, aerate and overseed at a heavier rate and you should be good. imo
  3. Teach123

    Teach123 LawnSite Member
    Posts: 155

    LOL. Yeah..he isn't licensed..but he is my retired father who is obsessed with lawns. He actually put the Halts down because he didn't know I was aerating this spring. It sucks, because he meant well, but I hate to reapply and risk over doing it.
  4. signature lawns

    signature lawns LawnSite Senior Member
    Posts: 401

    We do the aerations in the fall. That way we avoid any possibility of having a outbreak of Crabgrass after the pre-emergent is put down.

    I know of a competitor that aerated after Tru-Green did their pre-emergent application, and come mid July that particular homeowner had a huge outbreak in Crabgrass. The homeowner called me over to ask for my opinion about the outbreak while I was at his neighbors house. When I looked closely, all of the crabgrass plants where emerging from the edge of the aeration holes. He ended up hiring us the next year after noticing his neighbor didn't have the same problem.

    So I would say it definitely breaks the barrier. I noticed you said "Halts" which I believe is the active ingredient Pendemethalin which is inferior to "Dimension" or the active ingredient Dithiopyr. Dimension has some post emergent activity in addition to the pre-emergent, so you end up getting more bang for your buck with Dimension.
  5. Teach123

    Teach123 LawnSite Member
    Posts: 155

    So you are saying I should reapply after aeration? Or should I just hold off on the aeration until Fall? Here's the deal. The pre-emergent hasn't even been absorbed into the soil yet. Does this change anything?

    Thanks again for your professional advice
  6. humble1

    humble1 LawnSite Silver Member
    from MA
    Posts: 2,499

    as far as i am concerned the product is down, it rains there is your barrier, period.

    break the barrier by dethatching and aeration then spread seed, if your lawn is in good shape do it in the fall. After you aerate and seed do not apply more pre emergent as it will also kill new seed.
  7. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 12,219

    Research from Michigan State says you can aerate after application of crabgrass control.
  8. signature lawns

    signature lawns LawnSite Senior Member
    Posts: 401

    My opinion would be to hold off on aerating until fall. In fall the soil temps are going to keep going down, in spring the soil temps keep rising. For that reason alone is why my theory of doing the aeration in the fall is best. When the plug of soil is brought to the surface, you're also bringing up thousands of weed seeds. That said, soil temps rising in the spring make a perfect recipe for the weed seeds to germinate. So we avoid that altogether by doing the aeration in the fall. Some will argue otherwise, but I've noticed first hand what happens doing it the other way around. Your choice though, if the lawn didn't receive any water after the application, then the application hasn't been activated yet. You might be ok if you already scheduled the aeration for the customer. Good luck:)
  9. kirk1701

    kirk1701 LawnSite Gold Member
    Posts: 3,981

    1. Wait till fall to do the aeration.
    2. Don't try to reapply even if you do aerate as now your talking about putting down more nitrogen (since scotts is high in N to begin with) on top of what you have already applied and then your creating yet another problem, burning up your lawn.
    3. Check out your local Co-OP and get away from Scotts. There's much better and much cheaper products that work much better.
  10. White Gardens

    White Gardens LawnSite Fanatic
    Posts: 6,776

    Personally, I agree with the multiple above posts.

    Wait until fall to aerate. You get the most out of fall aeration over a spring aerate.

    The frost heave in the spring is the best compaction breaker. Doing an aeration in the fall helps to break the year's compaction and to help promote root growth for over-wintering.

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