Crabgrass and Overseeding

Discussion in 'Turf Renovation' started by Oroman, Aug 31, 2017.

  1. Oroman

    Oroman LawnSite Member
    Messages: 8

    I have a question I can't seem to get a straight answer to. I plan on overseeding my lawn within the next 30 days. No surprise, I have multi tiller crabgrass. Do I need to kill or remove (pull) crabgrass prior to overseeding? Or can I reseed over active crabgrass after dethatching? If I decide to kill crabgrass with Drive, do the dead roots inhibit overseeding?
     
  2. oqueoque

    oqueoque LawnSite Gold Member
    Male, from Jersey
    Messages: 3,275

    Dethatch it in two directions at 90 degrees to each other after it has died from the Drive, 7 to 10 days. 99% will uproot. Blow the dead crabgrass into piles. Rake it up & remove. Then seed,unless you are using bluegrass, which you will have to wait longer to seed. Read the Drive label completly 1st. You can rent one machine that will dethatch and slit seed. We have an Exmark. Others make them also.
     
  3. Oroman

    Oroman LawnSite Member
    Messages: 8

    Thanks Oqueoque:

    So I gather overseeing over the active crabgrass is not an option for success? What if I pulled all crabgrass? Any extra benefit? Especially if the Drive is not fully successful......
     
  4. oqueoque

    oqueoque LawnSite Gold Member
    Male, from Jersey
    Messages: 3,275

    The drive will be successful. It needed spot spray a 2nd time. You need seed to soil contact. I have done this to lawns that were mostly crabgrass. It is not that difficult. The dethatcher rips it right up if it is dead, and removes some living.
     
  5. oqueoque

    oqueoque LawnSite Gold Member
    Male, from Jersey
    Messages: 3,275

    All the dead plant material, including crabgrass will come up like this.
     
    hort101 likes this.
  6. oqueoque

    oqueoque LawnSite Gold Member
    Male, from Jersey
    Messages: 3,275

    Try to rent a machine that dethatches & slit seeds like this. It dethatches & seeds.
     
  7. M125X

    M125X LawnSite Member
    Messages: 10

    Good videos! I've used the Drive XLR8 and two applications seeems to be what is needed for some areas of crabgrass.
     
    oqueoque likes this.
  8. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,671

    I say seed on top of the crabgrass--because you cannot really plan to seed in spring when there is a crabgrass problem. Depends on how much of the old grass is worth saving.
    Perhaps let it get tall--then cut it really short--removing debris. Its a shock to the system--but it exposes some bare soil. Both grasses are damaged, but crabgrass cannot come back--when weather is cool. If you want to rake, power rake or use a nail drag at this point--that would expose even more bare soil. I think use double the usual amount of seed, as germination is low in an overseed situation.
     
    Mr Efficiency likes this.
  9. Oroman

    Oroman LawnSite Member
    Messages: 8

    My concern with seeding over crabgrass that is still alive is whether the seeds will be able to germinate through the existing (and alive) crabgrass leaves and roots. My 3,000 sf lawn is about 35% infested. Since I need to lay seed (cold weather fescue mix) toward the end of September when soil has cooled down, the crabgrass will not have died from the cold yet. However, you think cutting the lawn (and crabgrass) as short as possible and power raking will remove most of the crabgrass at the ground surface (leaving behind the rather small root stems) to provide adequate seed to soil contact?
     
  10. Mr Efficiency

    Mr Efficiency LawnSite Senior Member
    Messages: 731

    Crabgrass will be dead in a m
    Not sure where you live but here in NJ Crabgrass is almost done growig and will be dying soon, I would apply starter Fertilizer, water in and soften soil, mow the lawn down short to cut down Crabgrass and core areate or Spike and over seed. Bit of waste to spray drive now and you should be getting the seed in sooner then so late in Sept if some doesn't grow and end of September
     
    CorgiTurf likes this.

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