Crabgrass preventer failed

Discussion in 'Pesticide & Herbicide Application' started by Green Boys LawnCare, Aug 19, 2007.

  1. Green Boys LawnCare

    Green Boys LawnCare LawnSite Member
    Messages: 84

    I was hoping to figure out what I did wrong. I applied a granular product with fertilizer and Dimension (0.107%). I made 1 application, and applied the product around April 1st, which is right about the time you start mowing around here (Kansas). I applied at the suggested rate for the transition zone of ~4 lbs/1,000 sq. ft. for grass that is cut tall, because I mow these lawns around 3 inches. For short cut grass like golf courses they recommend ~8lbs/1,000 sq. ft. It's now August and just about all of these lawns are getting crabgrass. So, any ideas on what I did wrong? Is Dimension the product of choice? Should I have applied at the higher rate or made 2 applications? We got heavy rain after I made the application, would this affect the herbicide? I appreciate any help.
  2. carcrz

    carcrz LawnSite Silver Member
    Messages: 2,085

    ground temp below 60*?
  3. MStine315

    MStine315 LawnSite Senior Member
    Messages: 789

    What has your weather been this year? I know it's droughty in a lot of places. What happens in a drought year is, the crabgrass doesn't germinate when soil temps. reach the normal target temp. because it's dry. When we do get rain later in the summer the crabgrass germinates, the efficacy of the pre-emergent, regardless of the product, has worn off and is ineffective. If this is the case, there's really no good answer, unfortunately.
  4. Jason Rose

    Jason Rose LawnSite Fanatic
    Messages: 5,858

    We had a LOT of rain this spring, I think that's true for the Topeka area as well. There's just no way for the chemical to lock into the soil and stay there with as much rain as we saw. Then couple that with HEAT over the past month and a half...

    I have been doing a split app of dimension the past few years and usually always have lawns that end up with patches where I don't think 5 apps could keep the crab. from germinating. I don't think you did anything wrong, other than you could have gone a split application. The weather just never cooperates!
  5. scweedman

    scweedman LawnSite Senior Member
    Messages: 499

    I agree with carcrz ground temp is key.
  6. Harley-D

    Harley-D LawnSite Senior Member
    Messages: 508

    What about pounds active in the soil? You only had 0.17lbs/active/acre. I would say that for a good shot at control, you gotta get .42-.47lbs down in split apps. for great results. We do Early march and early to mid may here. Even get good control of some broadleafs.

    Dow did their research and boast certain results for 0.25-0.4 but then again they did the testing and i bet their a little bias.

    Green boys, just try a split app next year and make sure your putting enough active down. You'll see much better results.
    0.10% dim @ 4lbs/k is
    4 X 43.56=174.24
    174.24 X .001(dim as a percent)=0.17lbs/active/acre
    If going any heavier with that dim isn't good because of the fert it's tied to, try a 0.15%active with 13-2-5 fert. Not as much surge growth in the spring and good amount of active.
  7. pshields

    pshields LawnSite Member
    Messages: 20

    Dimension did not fail, it just ran out. I believe it is expected to control for 12 weeks. This is the third year I have used Dimension and have always had crabgrass show up in late July (about 14 weeks). This year I applied another application in early July and only have a few crabgrass plants showing up. Since Dimension will control small crabgrass plants, I wonder if we could wait until at least early May to apply and still be ok.
  8. mdlwn1

    mdlwn1 LawnSite Silver Member
    Messages: 2,443

    Dimension is the perfect late application as it offers pre and post on crabgrass(up until the tillers or so) We always used barricade...(can be done in march)..and would switch to Dimension for new and late signing customers.
  9. mdlwn1

    mdlwn1 LawnSite Silver Member
    Messages: 2,443

    I don't quite understand the reasoning for split apps. We use a single barricade or dimension app and have never had an issue. 16 years ago we used treflan in 1 app and only sometimes when it was really hot all summer did we have a very small amount of late season crabgrass.
  10. Rayholio

    Rayholio LawnSite Bronze Member
    Messages: 1,461

    We do 2 full apps of pre-m.... the early spring - and late spring.. very few problems. all of my recently signed customers (tru-green or other lcos) are all having crabgrass -and other weed problems.

    so, We just expected the unexpected... it paid off this time :)

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