Vinegar as weed killer questions

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Vinegar as weed killer questions

Postby Green » July 25th, 2017, 1:20 pm

I've sprayed vinegar before, but this was my first time doping it on a large scale, in a tank sprayer, with dish soap added in. I mixed about 1/3 vinegar to 2/3 water, and added about 5x as much dish soap as you'd use to wash dishes. My grandfather had a bunch of weeds growing in hardscape areas, including horseweed, crabgrass, bull paspalum, violets, ground ivy, and various other things.

Those mixing proportions should have been adequate, right?

How long until it's rainfast?

An added bonus was that the vinegar and soap solution helped clean my sprayer out.
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Re: Vinegar as weed killer questions

Postby coreyndstuff » July 26th, 2017, 11:41 am

I'm really curious about this too. Did you just spray? I'm curious day by day what it looks like (ie on the day of spraying it didn't change, next day it started to go, etc.) I'm considering using this method to spot spray in my yard.
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Re: Vinegar as weed killer questions

Postby 1977212 » July 26th, 2017, 2:16 pm

being that vinegar only kills the top growth wouldn't it require 3+ applications to succeed in killing?
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Re: Vinegar as weed killer questions

Postby Green » July 26th, 2017, 8:04 pm

1977212 wrote:
July 26th, 2017, 2:16 pm
being that vinegar only kills the top growth wouldn't it require 3+ applications to succeed in killing?
Why? If it's truly an herbicide, it should translocate to the roots. Number of sprays needed to kill success doesn't necessarily have to do with just translocation potential.
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Re: Vinegar as weed killer questions

Postby andy10917 » July 26th, 2017, 8:38 pm

It's not an herbicide by design, it's Vinegar. This is why you can mix it with oil and put it on your salad.

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Re: Vinegar as weed killer questions

Postby TimmyG » July 26th, 2017, 9:53 pm

Green wrote:
July 26th, 2017, 8:04 pm
If it's truly an herbicide, it should translocate to the roots.
Buzz! From Why It Can Be Dangerous To Use Vinegar To Kill Weeds:
Vinegar is a contact or “burndown” herbicide, killing what it touches within hours or days. The worst part is, it looks like it’s working, but then weeds resprout from the roots, particularly perennial species.
I didn't need to search to know that; I just wanted to cite a reference for what I wanted to say. Vinegar is not an effective herbicide, most notably because it does not translocate to the roots.
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Re: Vinegar as weed killer questions

Postby Green » July 26th, 2017, 11:33 pm

Interesting.

I've just learned the difference between burndown and "full kill" (for lack of a better term). So, it's more like torching it versus killing? Must be why it's called chemical burndown.

Today, I sprayed some spurge in the sidewalk with the same food-grade vinegar, but full strength and with no soap surfactant in it. It was brown within hours. We'll have to see if it comes back or not.

I appreciate the info. That said, I'm thinking that this "burndown" method may good enough for the purpose I'm using it for...clearing weeds out of hardscape areas quickly.
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Re: Vinegar as weed killer questions

Postby ken-n-nancy » July 27th, 2017, 9:18 am

My perspective for a "contact" herbicide - that kills the plant wherever it contacts it (but only where it contacts it) is that it provides generally the same effect as snipping the plant off at ground level. Doing that kills some weeds that can't regrow from the roots, but to others is just a temporary setback. Of course, repeated applications (or snipping at the surface) made soon enough will eventually deplete the energy reserves in the roots and kill the weed after some number of treatments (or cuttings).

Any residual effect from such "contact" herbicides is from having some of the herbicide remain at the soil surface where it can kill off any newly-emerged plant growth.
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Re: Vinegar as weed killer questions

Postby Green » July 27th, 2017, 10:04 pm

That's a good assessment.

In the case of the horseweed, I coated the entire stalk.
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Re: Vinegar as weed killer questions

Postby bernstem » July 31st, 2017, 9:01 am

Household vinegar (like what you use on your salad) is unlikely to be effective at killing plants - at least it never worked for me. Horticultural vinegar is a much higher concentration of Acetic Acid (~30% vs ~5%) and will work better, but is also potentially dangerous. You don't want to eat it, and certainly don't want to get it in your eyes.

Vinegar basically kills the portions of the plant you apply it to. Many weed will regrow from the roots and will require repeated applications. Some, like Nutsedge, will probably never be fully killed with Vinegar.
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Re: Vinegar as weed killer questions

Postby Green » August 2nd, 2017, 12:00 pm

The Spurge I sprayed is regrowing a bit...but I can just hit it again. It only takes a little bit of mist to burn it out. And, since food grade vinegar is safe if I get it on my hands, I don't have to worry about using gloves, washing hands immediately after, etc. It's not a replacement for Roundup by any means, but I think it still has a use.

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