# What to do about a LOT of crabgrass



## video1 (Jul 17, 2020)

As you can see, my lawn is inundated with lots of this stuff. Should I just kill the entire lawn by adding more topsoil (since I need to level it out anyway) or should I use a weed killer? Is the weed killer safe for my kids and dog?

Closeup of the invader:


Overall look of the lawn:


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## video1 (Jul 17, 2020)

OK I've been reading about solarization. Can I cover the area with a tarp for a week or two? It's 95-105 degrees every single day right now. I know that kind of heat will kill everything under a tarp. Then can I just come back and dethatch and/or aerate that part of the lawn and lay down new seed after application of acid or base to neutralize the soil?


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## dacoyne (May 27, 2018)

Just spray Tenacity to kill just the crabgrass and then seed in the fall. No reason to make more work for yourself than you need too.


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## video1 (Jul 17, 2020)

dacoyne said:


> Just spray Tenacity to kill just the crabgrass and then seed in the fall. No reason to make more work for yourself than you need too.


I'm trying to do this with out any of the chemicals. I just don't trust that they are not carcinogenic. I've survived cancer once. I'm not going to give it another chance.


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## dacoyne (May 27, 2018)

Gotcha, solar works but you are going to smoke everything under the tarp.


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## ABC123 (Jul 14, 2017)

Weed killers are always safe for the most part after It's dry. Quinclorac will get rid of it but it also asks to use MSO surfactant to work better.

Frost will also kill it but were a few months away from that. That's why a pre emergent is very important for weeds.


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## video1 (Jul 17, 2020)

dacoyne said:


> Gotcha, solar works but you are going to smoke everything under the tarp.


Well if you look at the pics, most everything is crabgrass anyway lol. I figure if I kill it all, then I can come back and aerate it, and then seed it. That's my preliminary non-chemical "natural" plan right now, unless others show me a better way to do it with chemicals that are non-carcinogenic. I'm just deathly afraid of these chemical companies and their claims about being "safe". I understand not everyone feels the way I do about that subject and that's ok. I'm here to learn, not preach.


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## video1 (Jul 17, 2020)

ABC123 said:


> Weed killers are always safe for the most part after It's dry. Quinclorac will get rid of it but it also asks to use MSO surfactant to work better.
> 
> Frost will also kill it but were a few months away from that. That's why a pre emergent is very important for weeds.


I'm in zone 9b, in the Sierra Foothills of Northern California where it's routinely 95-110 degrees every day for the next couple more months or longer. It's 10pm right now, and the temp outside is still 81 degrees. But "it's a dry heat" lol!!!


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## corneliani (Apr 2, 2019)

However you decide to kill off the existing vegetation be aware that these plants grew from a bank of seeds inside of your soil profile to start with. They'll come back year after year until that seed bank is depleted. You can reduce the rate of germination by having a deep growth of preferred vegetation (ie turf) to "own" that parcel of land to some extent and crowd out invading weeds, but that's a tough task. Hence the use of chemicals to selectively suppress certain vegetation in preference of others.

If you decide to go down this path don't kill off the existing weeds until it's time to plant the new turf. Bare dirt is an invitation for opportunistic vegetation to grab a foothold in.


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## dacoyne (May 27, 2018)

corneliani said:


> However you decide to kill off the existing vegetation be aware that these plants grew from a bank of seeds inside of your soil profile to start with. They'll come back year after year until that seed bank is depleted. You can reduce the rate of germination by having a deep growth of preferred vegetation (ie turf) to "own" that parcel of land to some extent and crowd out invading weeds, but that's a tough task. Hence the use of chemicals to selectively suppress certain vegetation in preference of others.
> 
> If you decide to go down this path don't kill off the existing weeds until it's time to plant the new turf. Bare dirt is an invitation for opportunistic vegetation to grab a foothold in.


+1 to this, nailed it!


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## gmorf33 (Jul 30, 2019)

video1 said:


> dacoyne said:
> 
> 
> > Gotcha, solar works but you are going to smoke everything under the tarp.
> ...


You'll have a hard time keeping crabcrass from coming back without any chemical pre emergent. Even with a thick lawn it will pop up in any space it can find. Remember crabgrass is annual and drops a TON of seeds. Those seeds can survive for years. If you truly want a lawn without crabcrass when you already have this much in your lawn (hence lots of seeds), i don't know if it's possible without a preEm. Check into prodiamine for research on its safety and see if its something you can be comfortable with. If not, you might have to just resign to living with crabcrass.

As a side note... Keep in mind that prodiamine is meant to get into the upper layers of the soil and make a barrier, so once it's watered in, you shouldn't be having any kind of contact with it. Make sure you wear proper PPE when applying it (love sleeves, gloves, rubber boots, face mask) and you should be more than ok. Though as a cancer survivor, i can understand why you would be very hesitant and don't blame you for your caution.


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## video1 (Jul 17, 2020)

Thanks for the thoughtful reply. I think you're right. About half the lawn is crabgrass. Maybe I should just hire a tractor service to strip it all away. But even then as you say, the seeds are down there and will sprout up again next season. UGH!!!

[/quote]

You'll have a hard time keeping crabcrass from coming back without any chemical pre emergent. Even with a thick lawn it will pop up in any space it can find. Remember crabgrass is annual and drops a TON of seeds. Those seeds can survive for years. If you truly want a lawn without crabcrass when you already have this much in your lawn (hence lots of seeds), i don't know if it's possible without a preEm. Check into prodiamine for research on its safety and see if its something you can be comfortable with. If not, you might have to just resign to living with crabcrass.

As a side note... Keep in mind that prodiamine is meant to get into the upper layers of the soil and make a barrier, so once it's watered in, you shouldn't be having any kind of contact with it. Make sure you wear proper PPE when applying it (love sleeves, gloves, rubber boots, face mask) and you should be more than ok. Though as a cancer survivor, i can understand why you would be very hesitant and don't blame you for your caution.
[/quote]


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