Since you're spraying the foliage with a solution of vinegar and not the soil, any impact on the soil should be minimal and will be even further reduced through rainfall.

It depends on the native soil. Here in Madison, Wisconsin, our native soil is high in clay content, and also has considerable eroded limestone. The pH is around 7.6. I can pour vinegar(5% grocery store white vinegar) on dandelions to kill them, and this will kill a small circle of nearby grass, but the soil is so alkaline that the vinegar is neutralized, and the grass grows back in 60 days. Also, vinegar is broken down by soil bacteria, and it tends to disappear over time.

The soil here is already acidic - Nova Scotia, Canada. The patch where the goutweed is growing is amazingly gorgeous - beautiful black gold. I think someone in the past may have used it as a garden waste area since I'm finding 'gardening' stuff in it such as a wire pot. We are not used to such soil here.

There's no doubt I'm spraying on the soil as well. This is a sprayer which works with a pump, not some small spray bottle.

I don't plan on planting in that area this year and was planning on concentrating my efforts to simply eradicate this weed there and establish gardens in other areas of the property.

Glad to hear the vinegar will be dealt with by soil bacteria and time. :O)

To make a difference in your soils pH you would need to apply gallons of vinegar. Spraying that Goutweed more than likely would not add enough vinegar to your soil to have much, if any, affect. Now if you were to use Acetic Acid that might be different, but you could be easily burned by that stuff as well as your plants.

Thanks! This seems to be working.

To make a difference in your soils pH you would need to apply gallons of vinegar.

If you are using table vinegar (5-7% concentration), then this is true. However, horticultural vinegar (20% concentration) can alter soil pH........altering the pH is one of the methods this product utilizes to kill plants. However, this effect is typically not overly long lasting and can be mitigated by liming.

I never heard of goutweed before, so I did a bit a research. Turns out in the NE US it is considered a noxious invasive weed. It is prohibited or banned from planting in CT, MA and VT. It develops and spreads by underground rhizomes. It has proven very difficult to control. One method by which it spreads is be being dug and discarded as yard refuse, where it regrows from discarded rhizomes.

As far a vinegar being used for weed control, most likely what you will see is burning of the tops, but neither the roots nor the rhizomes will be killed. USDA did a study using both vinegar strength (5% acetic acid) and 20% acetic acid. As you might expect, the 20% worked better. But what they observed is that after the treatments were stopped mature weeds grew back, with only young new weeds being controlled.

You might want to consider the physical control method, described in the link below, instead of vinegar.

Here is a link that might be useful: Plant Conservation Alliance - Goutweed

TXEB, you wouldn't happen to have a link to that USDA study, would you? TIA.

Link to the most recent USDA ARS report below.

Also from NM State University, a 2004 Extension article titled "Vinegar as Herbicide" noted the following:

Another factor to consider in New Mexico and the rest of the Southwest is that our dry climate results in rapid production of a waxy cuticle to protect plant leaves, especially weed leaves. This coating prevents the absorption of vinegar by the plant. Newly germinated seedlings have a thinner waxy cuticle protecting their leaves. This is also true of plants growing rapidly (after a rain or irrigation and fertilization). Plants with a thinner protective cuticle are more susceptible to treatment with vinegar herbicides. To maximize your success, water and fertilize the weeds before treatment to encourage rapid, unprotected growth.

Vinegar is not translocated from leaf to root in plants, so it will only burn the top from perennial weeds with a well-developed system of roots or rhizomes below the soil. These plants will quickly re-grow after treatment. Frequent re-treatment may allow you to manage these perennial weeds by eventually depleting the reserve of food stored in the roots of these plants.

Here is a link that might be useful: Vinegar as a burn-down herbicide

This is actually a good question, as much for what is not directly asked for as for what is asked.

Consider for instance, the relative merits of using a contact herbicide to control a week known for a vigorous and spreading root system. Also known as, good luck with that.

If I were to ask about using 2,4-D or glyphosate, there would be no end of people seeking to educate me about the risks inherent in the use of a chemical, even if no apparent risk was observable. Hence, the concept of risk-cup analysis, as if I were unaware of what it was.

But since this is an approved 'organic' practice, there is no perceived downside, despite the rather obvious conclusion of what happens when you continuously apply a product with a pH of...what, precisely? to the same area. If idiocy is rampant in the use of chemicals, is it any less rampant in the use of non-chemical chemicals?

To be honest, I don't think I can answer the question of any possible side effects. The risk of altering the pH to the point of essentially sterilizing the soil is a very real one, but I don't know under what conditions or for how long it is likely to occur, and I find it a little astonishing that people are not willing to apply the same level of critical thinking to 'organic' practices as they purport to apply to chemicals. Also known as, the modern enigma of science in American culture, or, if you agree with me you are a wise, rational being who thinks clearly and well, if you don't, you are moronic idiot who shouldn't be allowed to reproduce, much less do the Most Evil Thing Ever, which is say something I don't agree with.

But at the same time...if I were to package horticultural vinegar in a container that said, Made by Monsanto, how long would it be before vinegar were the new Evil Likely to Control the World?

I used to use vinegar, mixed with our local tap water, supplied by the city, to lower soil pH around our blueberry shrubs. Our tap water comes from city wells, that are drilled down into limestone aquifers, and it has pH around 7.6. To summarize, watering blueberry shrubs with a mixture of tap water and vinegar works OK, as a method of lowering soil pH, if done with care. But the effects are temporary, and you have to keep repeating the process. It is thought that bacteria in the soil consume the vinegar, as a food source, so it disappears in about a month. I consider vinegar to be a chemical, and I would be happy to buy some from Monsanto, if it was available locally.

TXEB, thanks for the link.

strobiculate, too funny. I think you nailed it.

Posted by strobiculate none (My Page) on Wed, May 29, 13 at 8:27

This is actually a good question, as much for what is not directly asked for as for what is asked.
Consider for instance, the relative merits of using a contact herbicide to control a week known for a vigorous and spreading root system. Also known as, good luck with that.

If I were to ask about using 2,4-D or glyphosate, there would be no end of people seeking to educate me about the risks inherent in the use of a chemical, even if no apparent risk was observable. Hence, the concept of risk-cup analysis, as if I were unaware of what it was.

But since this is an approved 'organic' practice, there is no perceived downside, despite the rather obvious conclusion of what happens when you continuously apply a product with a pH of...what, precisely? to the same area. If idiocy is rampant in the use of chemicals, is it any less rampant in the use of non-chemical chemicals?

To be honest, I don't think I can answer the question of any possible side effects. The risk of altering the pH to the point of essentially sterilizing the soil is a very real one, but I don't know under what conditions or for how long it is likely to occur, and I find it a little astonishing that people are not willing to apply the same level of critical thinking to 'organic' practices as they purport to apply to chemicals. Also known as, the modern enigma of science in American culture, or, if you agree with me you are a wise, rational being who thinks clearly and well, if you don't, you are moronic idiot who shouldn't be allowed to reproduce, much less do the Most Evil Thing Ever, which is say something I don't agree with.

But at the same time...if I were to package horticultural vinegar in a container that said, Made by Monsanto, how long would it be before vinegar were the new Evil Likely to Control the World?

This post was edited by TheTradition on Tue, Jun 4, 13 at 19:56

If someone were to ask about using 2,4,D or glyphosates, or any of the other many synthetic stuff, on an ORGANIC gardening forum they may well be told there that thosae are not acceptable ORGANIC products, but on this forum I have not seen anyone told that in the many years I have been here.
How much lime is needed to raise a soils pH from, say 5.5 to 6.5 ranges from 0.5 tons (1,000 pounds or about 0.43 pounds per square foot) per acre on sandy soils to 4.3 tons per acre on muck soils. So if vinegar would change a soils pH diluting a gallon by half and spraying that over 1,000 square feet is not going to do much. Maybe, possibly, applying a gallon of vinegar, undiluted, over 100 square feet might do something.

A simple calculation -- 1 gal of typical household vinegar @ 5% acetic acid (AA) contains 6.8 oz. of AA. Treating this as a simple and complete neutralization of pure calcium carbonate (dibasic), that AA would neutralize about 5.7 ounces of calcium carbonate. Applied to 100 sq feet of soil at "plow depth" (2 millions pounds per acre), that amounts to ~ 77 ppm of calcium carbonate.

But with vinegar the effect won't be lasting. What's left behind after the neutralization is acetate, and that will degrade fairly easily, leaving in its wake either carbonate or hydroxide. So the lowering of pH with vinegar will be fairly short lived.

This post was edited by TXEB on Thu, Jun 6, 13 at 12:01

I had gout weed in two raised beds that I had in Wisconsin. I think it was brought in with the topsoil I used in the beds. I tried for 2-3 years to use organic methods to get rid of it, and it still spread. In my experience, the words "vigorously aggressive growth", were much too mild for this evil plant. I even dug through and sifted what I thought was every speck of dirt in both beds, hoping to get the rhizomes. I failed. After days of back breaking work, the weed came back with a vengence. The weed started to show up in the next bed over, and I was frantic. So in the early spring, as soon as the snow was gone, instead of planting veggies, I covered both affected beds with black plastic. It's called solarization of of the soil, and it kills everything in the soil. I left the soil covered all summer, and all winter as well. When I opened them up, I found no sign of gout weed, so I replanted veggies. I also added soil inoculants, and worms from other beds, because I was sure all of the beneficial micro-organisms and worms had been killed as well. The beds did well, and I had no more gout weed problems there. It did take me another 3-4 years to dig out all of the widely scattered progeny from those beds, but eventually, I stopped seeing gout weed.

Here's a question for the forum. If she covers the gout weed patch with black plastic, will it get hot enough in the shade to solarize the soil? My beds were in the full sun.

Here is a link that might be useful: Sun Solarization in Gardens and Landscapes

Whether soil solarization will work depends on how much sunlight is available. The further north one is the less effective solarization usually is.
Last summer, here, solarization would have worked, however, on average because of cloud cover solarization usually does not because there is not enough sun to get the soil hot enough, long enough.

Solarization to heat the soil should be done with clear plastic, not black plastic. The black will retain heat from radiative heating, but you won't get the solar heating from absorption of light and conversion to heat. In the shade, you won't get much heating at all.

Covering an invaded area with black plastic is one of the recommended methods for control, as I noted in a previous post above (see the ink to Plant Conservation Alliance - Goutweed). But the mechanism is to starve the plant by precluding photosynthesis, not soil solarization.