How do you kill weeds in cement cracks? FAQ

I've never had a problem. Roundup kills what's growing in just a week, as long as temps are warm. And the ground clear, extended stuff works for months. And that's at just average strength too.

what kind? and how are you using it?

depends upon what type of weed killer it is.

get the weeds dead, then take an air compressor and blow the dirt out and caulk the crack closed. weeds won't grow there if light, water and air can't get in.

songbird

I use straight vinegar. It doesn't kill as long as weed killer but then it doesn't leave a toxic mess either.

Instead of playing 20-questions, suppose we get back to the original question and you tell me what kind to use.

Would save everybody a lot of time.

That would take a lot of caulk.

Lay a flat metal strip over the crack. The metal strip plus some concrete anchor screws should do some good.

Roundup works well for me, but you do need to follow the instructions to make it most effective.

It's only a "long" crack. :)

Songbirds answer seems to me to have a good chance of "preventing regrowth" which is what the OP wanted.

Filling with polymeric sand might be an option. No personal experience with it.

My neighbors, trying to be nice, mowed a little piece of my lawn, including my new rose bush, 4 times. I was sure each time they killed it, especially the last time, but it came back again this year and had had two roses by the time I got back May 29th.

The lawn mower probably left 2 inches of the stem each time, but no leaves or flowers.

mike wrote: ...

you can fill it most of the way with other stuff and then just caulk the top part.

as for weed killer, any harsh chemical will often work for a short period of time but if the gap remains and is hospitable for any weed seed that blows or washes in... well, they'll come back.

i've used vinegar, ammonia, bleach, roundup, salt, boiling water, flames, but these days i usually pull them and let them bake in the sun for a few weeks before burying them. worm food...

songbird

I use Roundup and have a hard time believing it's not killing your weeds. Before applying though I do knock down those weeds with a weed eater then apply the extra strong solution along the whole crack, not just where those weeds are popping up. With the weeds chopped down they seem to absorb the Roundup readily and are quickly killed.

I bought the quart size, but I don't see it around now. Used it for my badly cracked driveway for the last 2 years. Weeds don't come back until the next year.

Applying roundup where there are no weeds is just wasting it and spreading more chemicals into the environment. It works by being absorbed into plant leaves and has no effect on emergence. You can spray an area with roundup t o kill weeds and seed it just a few days later.

With the weeds chopped down they seem to absorb the

It would be more effective without cutting them down. It works by absorptio n through the leaves. Agree that it's effective, I don't have any problem w ith it killing weeds in cracks either.

Thanks, I changed the subject line to more accurately reflect my desire. How do you PREVENT weeds from growing in cement cracks?

I have no trouble killing the weeds. It's a pita to get the dead carcass out of the crack. But they come back almost immediately. I'd like a semi-permanent solution. The ground clear stuff that claims to PREVENT weed growth for six months doesn't. No, I don't remember the brand, it's all used up and gone.

We've also got weeds growing up thru the tar they put in the cracks of the asphalt roadway.

On Thu 08 Jun 2017 11:44:15p, mike told us...

You'll never kill them permanently, but I've found a good dose of pure chlorine bleach kills them for quite a while.

ing more chemicals into the environment. It works by being absorbed into pl ant leaves and has no effect on emergence. You can spray an area with round up to kill weeds and seed it just a few days later.

ption through the leaves. Agree that it's effective, I don't have any probl em with it killing weeds in cracks either.

Are you spraying it up close, getting it into the crack? If it's light and only goes around the crack and not in it, it won't work. Using the pre-mixe d or concentrated, where you can determine the strength?

only goes around the crack and not in it, it won't work. Using the pre-mixed or

concentrated, where you can determine the strength?

I'm using undiluted concentrated stuff and pouring it into the crack. I'm assuming the stuff doesn't degrade in storage. It was probably 20 years old. Probably banned by now for being too toxic.

Nobody has suggested a currently available brand that they've used.

Weed killer will kill the weeds that are actively growing, but it will not kill the seeds that are still in the crack, which subsequently germinate and grow.

Keep using the weed killer every time weeds grow back.

Home ownership/maintenance requires constant vigilance and dogged persistence.

Cindy Hamilton

Look for pre emerge herbicides. Use of those plus the crop canopy are a couple of the farmer's weapons against weeds. This might sound odd but the main part of the weed could be outside of the crack. Some have roots that extend a long ways. The farmers here will know the term in an instant. Weed killers are a lot better than they were 30 years ago. Fields were weedy toward the end of the growing season back then. Now they're mostly clear even into early September.

I did. And I just applied it a couple weeks ago.