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? on soil temp and first treamtment

Discussion in 'Pesticide & Herbicide Application' started by GarPA, Mar 9, 2005.

  1. GarPA

    GarPA LawnSite Silver Member
    from PA
    Posts: 2,585

    According to the data that I've read over the years, the first prem app in spring is best put down when soil temps are sustained at least in the low 50's. Well here in the Mid Atlantic region I see the fert companies (TruGreen and some of some our local reputable companies) putting it down at end of Feb and right now..our soil temps here are in the upper 30's...I think.

    Your opinion on timing for this first app is appreciated
  2. Grandview

    Grandview LawnSite Gold Member
    from WI
    Posts: 3,251

    You want your Pre-M down before crabgrass germinates. Crab starts to germinates when soil temps reach 50 degrees. Ideally you want to apply it a week before that. That gives you the longest control and time for a barrier to form. Most Pre-Ms give you 8-12 weeks control, but they start to breakdown as soon as you apply them. I can not apply all of my Pre-M in one week, so I start April 1 and have until Mid May. I am in Wisconsin along Lake Michigan. I know some companies in this area apply straight fert in Round 1, and apply Pre-M in Round 2. I do this with some of my customers. Crabgrass does not poke around here until end of May/early June.
  3. GarPA

    GarPA LawnSite Silver Member
    from PA
    Posts: 2,585

    ok thanks...I think we're on the same page. Perhaps what I see them putting down is in fact straight fert, if it is pre-em. shame on them as some of it is bound to leach thru by the time the soil lets the c.g. start germinating.
  4. crabgrass germinates when soil temps at 3" depth reach 55 degrees for 3 consecutive morning at sunrise! Goose germinates at 5 degrees above crab!

    The pre emerge needs to be applied before soil temps reach these levels, and with enough time to activate the barrier! Now, how soon to apply a pre emerge before germination, depends on the length of control the pre emerge you choose gives, and the desire length of control you desire.

    If pre emerge is on a fertilizer carrier, you need to consider when the application is taking place, how active is the turfgrass plant growing, ( roots and stems) at time of application, are you trying to stimulate the root growth, stem growth, or both! This will determine what anaylsis of fertilizer you should pick! Another though, how much of the nitrogen is slow controlled release, and from what source!

    Hope this helps with timing of applications and choosing the proper fertilizer anaylsis!
  5. GarPA

    GarPA LawnSite Silver Member
    from PA
    Posts: 2,585

    good info tim and grandview...we sub out most of our of our fert properties because I dont have the expertise nor do I have the time to learn it know it like you guys know the formulations and performance given certain weather conditions. I know what I'm good at and not good at...and I'll let the chemical work mostly to you guys who know your stuff..thanks for the input
  6. whoopassonthebluegrass

    whoopassonthebluegrass LawnSite Platinum Member
    Posts: 4,214

    This isn't entirely true. Quality pre-emergents (such as Barricade) can be applied in the late fall even - and still be wholly effective. Until the soil temp reaches the level of typical biologic activity (50ish), they will just sit there dormant without suffering decomposition.

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