Seeding Into Crabgrass

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Bales9er
Posts: 379
Joined: June 8th, 2011, 3:38 pm
Location: Western Massachusetts
Grass Type: Lesco Double Eagle PR
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Seeding Into Crabgrass

Post by Bales9er » August 18th, 2019, 10:14 am

Has anyone tried overseeding into large crabgrass areas without killing it all off first? Wondering if there's been any success with this tactic since the crabgrass will be slowing down and eventually dying off instead of really trying to aggressively grow this time of year.

I ask because I don't have much spare time these days with two very young children and a busy job. I have a lot of large crabgrass areas and completely bare areas that I need to get grass growing in so my plan, if any of you think it will work, is to just drag my dethatcher around to rough up the soil then overseed with PR and water it properly. Not looking for a showcase lawn at this point just something serviceable.

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ken-n-nancy
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Joined: July 17th, 2014, 3:58 pm
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Re: Seeding Into Crabgrass

Post by ken-n-nancy » August 18th, 2019, 10:39 am

Bales9er wrote:
August 18th, 2019, 10:14 am
Has anyone tried overseeding into large crabgrass areas without killing it all off first? Wondering if there's been any success with this tactic since the crabgrass will be slowing down and eventually dying off instead of really trying to aggressively grow this time of year.

I ask because I don't have much spare time these days with two very young children and a busy job. I have a lot of large crabgrass areas and completely bare areas that I need to get grass growing in so my plan, if any of you think it will work, is to just drag my dethatcher around to rough up the soil then overseed with PR and water it properly. Not looking for a showcase lawn at this point just something serviceable.
I have done almost what you suggest. A few years ago, I did a "1-day renovation" on a 10'x12' patch of roadside lawn shared between myself and my neighbor that was pretty much all crabgrass. I did the following: (a) mowed at the lowest level on my rotary mower, using the bag to not cover the soil with clippings, (b) raked dead stuff out, (c) sprayed glyphosate in the morning, (d) after a couple hours to let the glyphosate dry, I hand-broadcast seed (KBG in my case), (e) started watering for germination.

This ended up working really well. The crabgrass didn't start looking dead from the glyphosate (don't use a combination product with diquat or other AIs) until about 5-7 days later. By then, I could see a few germinated seedlings down under the dead/dying crabgrass. The area really only looked dead for about another week, by which time the baby grass could start to be seen poking up above the dead crabgrass. Seeding into the dead/dying crabgrass helped with retaining seed despite rain (minimizing washout) and retaining moisture (dead/dying grass helps shade soil, instead of requiring peat moss or something similar). The area really also only looked dead/dying for about 1-2 weeks.

Bales9er
Posts: 379
Joined: June 8th, 2011, 3:38 pm
Location: Western Massachusetts
Grass Type: Lesco Double Eagle PR
Lawn Size: 5000-10000
Level: Some Experience

Re: Seeding Into Crabgrass

Post by Bales9er » August 18th, 2019, 12:13 pm

Thanks for the info but I'm wondering about not using RU at all...just mow the crabgrass as low as possible then seed over it. I think I'm going to give it a shot one way or another but I was curious if anyone has had success without doing anything to eliminate the crabgrass.

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ken-n-nancy
Posts: 2290
Joined: July 17th, 2014, 3:58 pm
Location: Bedford, NH
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Lawn Size: 10000-20000
Level: Experienced

Re: Seeding Into Crabgrass

Post by ken-n-nancy » August 18th, 2019, 1:10 pm

Bales9er wrote:
August 18th, 2019, 12:13 pm
Thanks for the info but I'm wondering about not using RU at all...just mow the crabgrass as low as possible then seed over it. I think I'm going to give it a shot one way or another but I was curious if anyone has had success without doing anything to eliminate the crabgrass.
The problem is that the crabgrass doesn't really start dying until after there's been a frost, which pretty much wipes crabgrass out. Even with nighttime temperatures in the 40s, if daytime temps are getting up into the 70s, the crabgrass will still be growing and competing with your baby grass. By the time you get a frost to kill the crabgrass, you'll have run out of time for much development of the new grass, maybe excepting the PRG.

If you don't try, you can't be sure, but until there's a frost event (crabgrass doesn't tolerate frost, unlike the northern lawn grasses of PRG, FF, KBG which will tolerate frost just fine) that crabgrass won't be declining much. To have a no-glyphosate approach into crabgrass be successful, what you really need is for an odd very early frost (mid-September?) to wipe out the crabgrass and give your new seedlings a chance.

Bales9er
Posts: 379
Joined: June 8th, 2011, 3:38 pm
Location: Western Massachusetts
Grass Type: Lesco Double Eagle PR
Lawn Size: 5000-10000
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Re: Seeding Into Crabgrass

Post by Bales9er » August 18th, 2019, 1:55 pm

Kinda what i thought but was hoping for an anomaly. I should know by now that there are no shortcuts if you want true success. Thanks for the reality check.

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