Getting weeds out of paving?

November 2, 2007 7:21 PM

What's the best way to get weeds out of brick paving?

We've got a paved section outside the back door. The weeds grow out from between the bricks. We've tried using a "whipper snipper" ("weed whacker"), but that resulted in a shattered glass door when a small stone was picked up by it. (We have glass on two sides of the area.)

We've tried poisoning the weeds, but you still have to dig them out. We tried covering a section with opaque plastic to kill the weeds without poison, but they didn't die after a couple of weeks and the plastic looks crap.

Currently, the most effective way is to dig them out with a screwdriver, but that's an awful lot of work, particularly for something that will come back.

posted by krisjohn to home & garden (20 comments total)

Roundup, or if that doesn't work, use a blowtorch.
posted by kanemano at 7:25 PM on November 2, 2007

High pressure washer (eg. Karcher) works real well for us and has the bonus of cleaning the pavers too. It's a couple days of work each year for the 500m^2 of pavers we have but must be faster than a screwdriver!
posted by polyglot at 7:34 PM on November 2, 2007

If by "best" you mean "most fun" then I think a blowtorch would be good, or maybe hydrochloric acid? You could also use gasoline (and burn them)
posted by delmoi at 7:35 PM on November 2, 2007

You can pay a neighborhood kid to do it. I made some small amount of money doing this as a child.
posted by Eringatang at 7:37 PM on November 2, 2007 [1 favorite]

Pressure washer works well, but be careful -- it can also dig out the sand that was probably put down as a substrate for your patio.
posted by mudpuppie at 7:50 PM on November 2, 2007

Something like this helps (I'd imagine there's an Australian equivalent supplier), and spray down the sand with a pre-emergent herbicide to keep them from coming back, or mix a granular in with fresh sand. There's no way to do away with them forever, seeds and such get carried in on the wind or feet.

As an aside, I had a neighbor that swore by urine as an herbicide - collect it and let it sit for a day or two before spraying with it - but I must admit, I never tried it. I figured a little weeding was better than the patio smelling like the back alley of a cheap bar...
posted by pupdog at 7:59 PM on November 2, 2007

We've always used a tiger torch to burn the weeds off. A pressure washer works too but you really should re sand the blocks afterwards.
posted by Mitheral at 8:06 PM on November 2, 2007

Powerwash works well, as mudpuppie suggests, but in the absence of that technology, a bottle of Round Up works great.
posted by nkknkk at 8:12 PM on November 2, 2007

salt. then hose it down.
posted by gesamtkunstwerk at 8:18 PM on November 2, 2007

Seconding RoundUp / Glyphosate. That shit knows its business.
posted by Jimbob at 8:32 PM on November 2, 2007

I use a thing that looks like a bent fondue fork. I'm not really about herbicides, because I have pets and kids.

Actually, lately, I've let the kids use the bent fondue fork thing, with okay results. Keeps them off the streets.
posted by padraigin at 10:04 PM on November 2, 2007

I dislike poisoning stuff - particularly as my paved area shoots water directly into my vege patch, so I dump boiling water on mine and, when they're dead and dry, go back along and sweep them away with a stiff broom.
posted by ninazer0 at 11:26 PM on November 2, 2007

You don't mention whether you own(or are invested enough in) the property to make improvements, but a fairly long-term solution would be to repave with landscape fabric under tightly joined pavers.

Otherwise, the propane torches work well. They're also fun to use for the first couple of months anyway, after that it's just general run o' the mill pyromania. YMMV.

Alternately, every time you boil something like pasta or eggs, you can pour the scalding water on the young weeds. Kills 'em pretty good.

You can also try using 'corn gluten meal' monthly or so. It will prevent sprouting seeds from becoming seedlings. It would work best if the gaps between your pavers would capture something the consistency of birdseed, otherwise it would probably just wash away.

And just to cover more options, highly concentrated vinegar (~15-20% acetic acid) can kill weeds. You need a source for it (specialty canning/preserving supply shops often have something close), and it works best in the summer heat, if you have any.

Oh, and don't salt your ground, it's really never a good idea.

On preview: ninazer0 got there first with the boiling water thing. Seconding...
posted by a_green_man at 12:45 AM on November 3, 2007 [1 favorite]

Round-up is good, but you need to add some pre-emergent herbicide to it as well. You'll kill the mature weeds, and prevent new ones from germinating. You'll have to remove the dead plants, but new ones shouldn't take their place.
posted by Shohn at 4:15 AM on November 3, 2007

If it's hot and sunny, plain household vinegar does a surprisingly good job for a while---it works on the leaves, and I've found it works best in the summer when you can spray it on the leaves and then let them bake in the hot sun. They will look all dead the next day, and they stay dead for a while, and it also seems to stop the weeds from coming back.
posted by leahwrenn at 6:30 AM on November 3, 2007

Try corn gluten.
posted by pracowity at 6:45 AM on November 3, 2007

"... researchers are careful to point out that (corn gluten meal) does not affect existing weeds and that the nitrogen in CGM will benefit existing weeds as well as desirable plants."

- PDF on corn gluten on this page.

Nthing that boiling water, vinegar, or a weed torch are very effective.

If your bricks are dry set in sand, retrofitting with landscape fabric underneath won't help the germination of seeds in the sand. Better to make sure you've got a good 6" base of quarry waste under your patio. I agree with greenman- don't salt your ground!
posted by oneirodynia at 11:46 AM on November 3, 2007

Don't the torches leave burn marks on the bricks? That has been what's kept me from trying that (since, otherwise, gee, fire is fun!)
posted by Goofyy at 4:33 AM on November 5, 2007

One moves the flame back and forth such that the bricks don't heat up but the weeds, being made of less sterner stuff, are incinerated. Plus you hold the torch so the end of the flame is just skimming the bricks thereby minimizing the heat imparted to the bricks.
posted by Mitheral at 6:27 PM on November 5, 2007

Plain old rubber gloves. You get a really good grip, pull slowly and get as much of the root system as possible too.

Then make it uninhabitable.
posted by mu~ha~ha~ha~har at 2:23 PM on November 9, 2007