Best way to treat crabcrass in a organic way

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

  1. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    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
  2. Dr.NewEarth

    Dr.NewEarth LawnSite Bronze Member
    Messages: 1,476

    Crabgrass simply says that, the soil is low in calcium and that it cannot support decay starting with actinomycetes molds.

    It is usually possible to adjust the system in a year or two, putting a little calcium lime and sulphur or gypsum on the soil in order to restructure the pH.

    As this is accomplished, most of the infestation dissipates, virtually rotting away.

    Usually application can be computed on the basis of 1500 pounds of high calcium lime per acre, 30-40 pounds of processed and active sulfur per acre. If ammonium sulfate is used, a little more calcium is required.

    so, I would check your pH and raise or lower it accordingly so that you get as close to
    a neutral aka 7 on the pH scale.

    You can get a pH kit at the H.D. I just picked up one in the spa department.
    I think it was 15 dollars for a couple dozen tests.

    A basic soil test kit there is about twenty dollars. It will give you the macro nutrients levels only.
    Last edited: Apr 11, 2011
  3. Kiril

    Kiril LawnSite Fanatic
    Messages: 18,334

    Crabgrass will grow fine in soils with high Ca. Don't assume anything here! Using these types of plant indicators merely tells you what might be occurring, and that you need to get a soil test.

    You need a lab test to calculate a liming requirement. In short .... get a lab test.

    You don't need a neutral pH to grow turf. Anything in the range of ~ 5.0 - 8.4 will generally work for most turf ... where 6-7 is optimum.

    Those kits are very inaccurate. Send an appropriate composite sample to a good lab.
    Last edited: Apr 11, 2011
  4. Dr.NewEarth

    Dr.NewEarth LawnSite Bronze Member
    Messages: 1,476

    The organic method I recommended has worked fine for me.

    Correct the pH and many of your lawn and garden problems will go away

    The point was to get rid of the crab grass. What I suggested requires an "optimum pH."

    The HD tests are a cost saving example.
    That information can be used by other people too.

    You do not always require an expensive lab test.

    A lab test will typically cost you over a hundred dollars. In Vancouver they are $120 plus 12% tax.

    I will not say any-thing else. Thanks and good luck with your crab grass problem.
  5. Kiril

    Kiril LawnSite Fanatic
    Messages: 18,334

    No offense, but I see crabgrass in soils that are hovering around neutral and are high in Ca. Don't play games with your soil, especially Ca .... get a lab test. In the states, you can get a soil lab tested (basic test) from $18-40.

    You do if you want actionable information .... unless you have lab grade equipment at your disposal.
    Last edited: Apr 11, 2011
  6. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    Thanks for indicating that timing is essential for CG application...

    Here the snow is finally gone and we hit 70 degrees on Sunday, but rain/snow mix for later this week... The squirt and ferts will soon be out for !!! CG Prevention !!! in a few more days for CG that couldn't possibly germinate b4 Memorial Day... and likely closer to July 4th...

    So I vote for your method of CG control w/CGM... :)
  7. 1506cmo18

    1506cmo18 LawnSite Member
    Messages: 60

    What does KBG stand for?

    The snow is just melted and I'm looking for a good product to spread on my lawns that need nutrients and a weed protection. Is corn glutten meal a good option?

    I'm also looking at spraying weeds with a vinegar solution, picking them out then adding a new compost material and seed.

    With the statement above, after spreading CGM i should wait 3 weeks to seed?
  8. JFGauvreau

    JFGauvreau LawnSite Bronze Member
    Messages: 1,298

    Kentucky Blue Grass.

    Watch out when you spray vinegar on your weeds, since it will also kill the grass.
  9. 1506cmo18

    1506cmo18 LawnSite Member
    Messages: 60

    I'm also in Canada, how did you make out spreading CGM?

    Do you still use it for nutrients?
  10. 1506cmo18

    1506cmo18 LawnSite Member
    Messages: 60

    After the vinegar is sprayed, do you guys remove the weeds and reseed?

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