Weed Killer

[keith]

Roundup breaks down in a very short time. There is *nothing* dangerous about it "soaking into the pavers". Don't get that vinegar and salt in a cut on your feet! :-/

[mkirsch1]

The something else is ROUNDUP.

[salty]

Completely impractical unless you want to use something that will make the ground more or less permanently unfriendly to plantlife. See also : Sodium chlorate mixed with Atrazine

This (below) would be a much better solution for you if you want to avoid using very nasty chemicals:

I use this torch, connected to a propane tank from my gas grill to keep the flagstone around my hot tub weed free. It's fast.

[salty]

My comment stands. Roundup would not be a problem at all for what you describe. Complete non-issue as far as safety for spraying all over your patio.

Unlike vinegar, roundup kills the roots or the weeds, so they don't come back, or spread. Vinegar doesn't kill the whole plant and root system. It just damages the existing foliage. If the roots aren't killed, the foliage will grow back quickly.

[Jim Elbrecht]

-snip-

If it is non-toxic-- then how will it help anything? All the major players have minimally toxic, with short 'toxic to animals' phases.

One hour- once a year- and be done with it.

It doesn't matter if your gravel base is 100 feet deep-- the weed seeds come from the top.

Jim

[norminn]

There is no need to flood the entire patio using Roundup...just spray the weeds according to instructions. One use should kill all the weeds, although tough waxy leaves may require two applications. Then, spot treat any new weeds (or pull by hand). Existing weed seeds may continue to germinate for a while, but once gone the patio should be easy to maintain. If there are lawn grasses adjoining the patio and growing between pavers, a barrier should help keep them out.

[HeyBub]

You need a two-step process:

1. Kill the existing weeds. Roundup, vinegar, propane torch, pull 'em by hand, whatever.

1. A liberal application of a pre-emergent herbicide to kill the weeds, spores, seeds, cuttings, tubers, and all the plant eggs remaining. You should use this herbicide every spring and it usually lasts the whole growing season.

[RickH]

Yes there is a good reason to flood it, there are probably 500 brick joints in both directions spaced 3 to 7 inches apart on a 40 foot by

20 foot area. Spraying the full length of those tens of thousands of joints takes literally days, if I spot spray then I'm waiting for the weeds to win the fight and show themselves. I could flood the patio in a 10 minute job, rather than, literally a 10 hour job of spraying each brick joint, then having the outer edges of every brick discolored by roundup oil and middle of each brick still dry. I'd rather every brick soak up a harmless non-oily sunbstance for consistent color and get the joints well flooded deep with killer all done in 10 minutes.

[Larry W]

The vinegar herbicide recipe does not call for table vinegar, but what at least one company markets as "garden vinegar" It is 20% acetic acid. Table vinegar is 4 or 5%. I'm not crazy about Roundup, but I wouldn't be so sure that 20% acetic acid plus salt is more environmentally benign than Roundup, especially in "flood" quantities.

[RickH]

There is no visible dirt, the weeds are between the brick joints. I suppose I could add just a little round up to the vinegar and maybe it wont oil-into the brick so bad. But I do need to flood the surface, there is no way in hell I'm gonna individually spray all those joints and have just the brick edges get stained. I'd rather flood then sweep it around until it drops between the tight paver joints, then hose it all down next day to wash the brick surface.

[clare]

The only problem is roundup is only a "killer". It kills what is green NOW. What you want is a soil sterilizer - which is, by definition, poisonous (at least to plants) and long-lasting. It will prevent new seeds from germinating. Corn Gluten is supposed to stop weeds from sprouting. Calmix from NuFarm is a common sterilizer -Bromacil and 2-4d. Methyl Bromide is no longer readily available, but worked. Anything with Prometon is also non-selective and residual. Pramitol and Sahara DG are other brands.

Do NOT get it anywhere you want vegetation to grow within a year or 2. DO NOT over-apply - as it can leach or wash out to areas where vegetation is desired -

[clare]

And where, praytell, will the run-off go - both when flooding and when washing down?????

A real good example of why herbicides have been banned in so many areas - total blatant mis-use due either to laziness or ignorance (or both)

[norminn]

Oil? Never have seen oily residue using Roundup. Your idea of flooding is not the same as mine, apparently. When you mentioned flooding, I pictured saturating the whole patio with R. Spraying the entire patio to cover all of the weeds should not take long. The entire weed does not need to be wetted...Roundup is taken up by the plant through the foliage and, providing one follows label instr., begins very soon to kill the plant. Remaining Roundup decomposes, IRRC, in about two weeks. It should be applied when one expects no rain for a couple of days. There are a few weeds with tough, waxy foliage, that are a little tougher to kill. Any foliage killer will probably leave behind unsprouted seeds, but the next crop should be much smaller and once eliminated should be very easy to keep clear. I avoid widespread use of poison, and combine good maintenance into the plan. Pulling one weed by hand before it produces seed might eliminate hundreds or thousands of plants. Gotta keep the R. away from desireable plants. I know nothing about the salt/vinegar treatment, but there are good plants that are very sensitive to salt, like rhododendron and azalea, so it isn't necessarily the best method for all weed problems.

[Roy]

=3D=3D An ATV with a small mounted sprayer could apply Roundup in less than five minutes in that small an area. Roundup drifts in wind...you have to be careful. Safer by far than the pre-emergent sprays and with no residue problem. There are also wide spongemop type applicators that you just drag/wipe over the patio. =3D=3D

[clare]

Mixing a surfactant with the roundup helps on the stubborn waxy or oily leafed plants. Dishsoap, or a few drops of Diesel fuel in the mix makes a big difference to those plants.

[clare]

Those self-feeding painrollers that are useless for painting your ceiling work good for roundup.

[HeyBub]

Ah, okay. Here's a solution that WILL work! Guaranteed!

1. Remove bricks.
2. Lay impermeable membrane (plastic sheeting, backerboard, etc.)
3. Replace bricks.

[Jim Elbrecht]

-snip-

Maybe in the desert- but in my part of the world that will only work for a year. Weed seeds are smaller than the gap between pavers- and will sprout as soon as there is enough moisture there to set things in motion.

Jim

[salty]

The OP has set so many parameters and objections, that I don't think his problem can be solved to his satisfaction.

If he doesn't like the weeds, and also doesn't like any of the effective methods for controlling them, then maybe he can't have bricks, and needs to start over with something completely different.

Perhaps a poured concrete slab capped with tile of some type, with grout between them. Maybe Mexican terracotta if he likes the color of red bricks.

[HeyBub]

Ah! Excellent point!

Amended suggestion:

1. Remove bricks
2. Lay impermeable membrane
3. Mortar bricks back into place.