pre ems before aeration

Discussion in 'Pesticide & Herbicide Application' started by launboy, Mar 7, 2005.

  1. launboy

    launboy LawnSite Senior Member
    from indiana
    Messages: 273

    if a spring time fert is applied with a pre em., will aerating after this affect the weed "barrier" that forms with the pre em?
  2. Williams Services

    Williams Services LawnSite Senior Member
    Messages: 269

    There was a study done by a university (I think) on this a few years back and their conclusion was that it did not. I think a few other guys weighed in that they had found the same thing. I'll see if I can dig that info up.
  3. launboy

    launboy LawnSite Senior Member
    from indiana
    Messages: 273

    that would be great Williiams thanks for the help so far. if you do find the that info please direct me to where i can find it also.
  4. Williams Services

    Williams Services LawnSite Senior Member
    Messages: 269

    Lawnlad (a great source of very helpful info) had a post on this subject.
    Here's the link.
  5. ns400r

    ns400r LawnSite Member
    Messages: 110

    Well this is where I think the test plot ( text book) world loses against the real world.

    I cant see how a material that forms a chemical blanket to kill emerging seeds could not lose its effectiveness after core aeration. We all know crab pops along edges of roads, driveways because the heat from pavement dries and cracks the soil, and breaks the barrier.

    Secondly why take the chance, In cool season turf core aeration is far better in the fall so why mess with it in spring and worry about crab coming thru.
  6. launboy

    launboy LawnSite Senior Member
    from indiana
    Messages: 273

    well say you wait 6 weeks from the pre em. was laid like mentioned earlier? how long is the chemical blankets effectiveness?
  7. Pilgrims' Pride

    Pilgrims' Pride LawnSite Senior Member
    from MA.
    Messages: 481

    Well NS (what does ns stand for?),

    I disagree on spring aeration.
    Since crabgrass needs heat and light to germinate. I don't see any difference in when you aerate.
    It doesnt get that warm in a 2-3 inch hole and it certainly doesnt get light.
    Yes crabgrass grows along edges of places of driveways and other hot spots.
    But conditions are usually different in those areas.
    How many times have you discovered that the turf has spread over the walk/drive etc. and isnt even growing in soil?
    I personally have never seen any impact on aerating in spring.
    I do in fact aerate for many reasons.
    Often I'll aerate a new account in spring to reduce thatch or relieve compaction.
    It doesn't make sense to wait till fall in those cases and I cant remember any crabgrass propblems as a result.
    Though some will consider me a barbarian I do occasionally aerate in summer for certain reasons.
    Of course fall is best and I will schedule aeration in fall when I can.
  8. GroundKprs

    GroundKprs LawnSite Bronze Member
    Messages: 1,969

    It was talked about at many trade conferences here in early 90s. You pull up plugs of soil on a lawn with pre-em already applied, and the pre-em is just dissolved back into the surface of the lawn. There is no loss of efficacy. Studies in cool season grasses done at Iowa and Michigan State; southern studies done earlier. All studies found no increase of crabgrass if aeration done after pre-em application.

    Most turf sources do say not to make it a regular practice. But if you have already done your app, and find a reason to aerate afterward, you're not going to create a crabgrass problem.

    And while aeration is generally recommended as a fall practice in cool season turf, there are numerous valid cultural reasons for spring aeration over fall, or in addition to fall. But if you've done pre-em app, and just want to aerate afterwards because you have time to make the $$$ at it, that is not a valid reason.
  9. Grandview

    Grandview LawnSite Gold Member
    from WI
    Messages: 3,251

    Aerating after a prem sould not affect weed control. The chenical just reforms the barrier after aeration. Theoretically the sooner you aerate after the application the better. I do aerations when I have time, spring, summer, and fall.
  10. ns400r

    ns400r LawnSite Member
    Messages: 110

    Well, I see you wanna start something here dont you :D

    I guess if you havent seen a problem doing this then I believe you, but for me Im usually so busy just trying to get rd 1's done before end of may I dont have time to aerate.

    i can see aerating before rd 1, then the prem but i cant see how the barrier can reform over a new hole.

    Plus crab is my biggest peve, so why would I wanna take the chance to make my one prem app less effictive?

    Oh, this is where my name comes from.


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