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Best way to treat crabcrass in a organic way

Discussion in 'Organic Lawn Care' started by JFGauvreau, Apr 9, 2011.

  1. JFGauvreau

    JFGauvreau LawnSite Bronze Member
    Messages: 1,298

    Ya just spread it like a normal fertilizer, or mix it with your fertilizer. However, like mention in the other posts, timing is crucial. It must be applied 4-6 weeks before the crabgrass seeds germinate in order to kill them.

    CGM has I believe a 10% slow release nitrogen already in it. Nothing big.

    Ya you can always put some compost and reseed the patches that killed the weeds with vinegar, however, if your gonna do that to each weeds in a 5,000sq/f lawn, you will find it quite slow lol
  2. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    Didn't Bill say you can overseed in 6 weeks?
    ... "it doesn't last 90 days more like 6 weeks that is why timing is so critical with CGM, if you are going after CG it should be applied as the soil temp is rising from 60 to 65 "

    Now you're saying 4-6 weeks b4 it will begin to work? So can I sow my KBG right along with the CGM as long as it germinates and grows some within th 4 week period?

    It is this kind of real world experience that makes it sound more like snake oil, all the time... :)
  3. JFGauvreau

    JFGauvreau LawnSite Bronze Member
    Messages: 1,298

    Yes, put down CGM 4-6 weeks before the time the seeds germinate. If you put it 2 late, the CGM will not have any effect and the crag grass seeds will germinate.

    And if you put down KBG at the same time of CGM, i'm not sure if it will work lol, since KGB takes 14-28 days to germinate, sometimes even longer depending on the soil temp. Maybe rye grass or fescue will be able to grow faster before the CGM has any effect.
  4. 1506cmo18

    1506cmo18 LawnSite Member
    Messages: 60

    So once the vinegar is on the weed, will it kill it right down to the route?

    or should I spray with vinegar then dig it up and spread soil and seed over top?
  5. phasthound

    phasthound LawnSite Fanatic
    Messages: 5,138

    Vinegar will not trans-locate into the root and kill the plant. It burns the foliage and interrupts photosynthesis. Several applications are required. Household vinegar will not do the trick, you need 20% vinegar. If you splash this stuff in your eye, you will have permanent eye damage. If you're willing to dig out the weeds, then get to work doing that, skip the vinegar.
  6. Five Points

    Five Points LawnSite Member
    Messages: 208

    The CGM is about 9 or 10 per cent, but the rate is like 20 lbs producct per thousand. Adds up to quite a bit of actual N per thousand doesnt it. Would you really want to add more fert to it. I am interested in comments on how well this works as for greening up the turf in the spring.

  7. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    2 pounds of N per 1000, OH YEAH! it will green it up alright, I hope you like to mow
  8. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    So if I were to use this stuff for lawns, I would have my dormant seed in place or soon afte the ground is thawed, Say about: Early March, ready for it to germinate when it warms up enough. Maybe late April-Late May, depending on th weather...

    Now, if the soil isn't warm enough to germinate KBG, by late May I really can't expect CG to pop until late June maybe July on this particular lawn... So possibly putting the stuff down in Mid May so its working by mid-late June is the best way to go...

    Not a bad time to fertilize also, since we know that early Spring causes thatch and shallow roots...

    Now the big question, When do CG germinate in your area, and how can you time it???

    When the forsythia blooms... :laugh:

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