Questions about crab grass and dethatching

Discussion in 'Turf Renovation' started by precator, Aug 20, 2012.

  1. precator

    precator LawnSite Member
    Messages: 70

    I plan to dethatch this coming up Saturday, if I spray crabgrass this evening will it die off by Saturday? If so, will the dethatcher machine pull up that dead crabgrass? Also, after I dethatch, what should I do with all the dead grass? Is it better to bag it and dump it, or to mulch it with my lawnmower?
  2. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,808

    My suggestion: No, the crabgrass may be brown--but not entirely dead by 5 days. The dethatcher will pull up some --not all of the crabgrass. Remove and dump residue. A slit seeder may be the better option, as it will put the seed into the soil where germination will be high. Add starter fertilizer, (according to soil test if possible), Sow seed (top quality, only) (use plenty of seed, as not all will germinate), water every day for 30 days.
    Add fertilizer to build thickness after 30 days and again at 60 days. Any remaining crabgrass will be killed by frost at about mid October.

    In the spring...if you think you need more seed...sow it about when the temp hits a high of 60 in March. Apply crabgrass control when the high temp hits 80. If you are lucky the new grass will be able to withstand the crabgrass control. Apply crabgrass control again after about 6 weeks--you want to be sure.
  3. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I realize that people remove organic matter from their turf, because they believe if it looks nice to them it must be best for all... removing organic matter from soil is like stripping the paint off a car...
    Are you worried about too much living thatch??, or dead grass thatch??? Run a slitseeder as Riggle suggested and skip the dethatching altogether, also it is unnecessary to kill annual weeds at this stage of the season, but it doesn't hurt anything either... their dead bodies act as cover for the seed...

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