Vinegar and Epsom Salt as herbicide

[Whwoz]

Over the last couple of months, google feeds on the phone have been showing stories about people using this mixture as a herbicide to "Make weeds disappear in 24hrs". Most of these feeds seem to originate out of the UK and are showing photos of/describing its use as a weed control agent around footpaths. Supposedly it "burns the plants away" within 24 hours.

Mixture is
2 cups Epsom Salts = Magnesium Sulphate
1 gallon (UK) Vinegar (does not mention acidity levels)
1/2 cup dish washing liquid soap as a sticker

Vinegar here is available in 2 liter bottles at 4% or 8% double strength, some feeds mention using apple cider vinegar. I used 4 liters of 4% acidity plain white vinegar.

First up this is definitely a contact burn type spray, not something systemic, so what ever you want to kill needs to be coated thoroughly with the mixture. Kill it will, make the plants "disappear" within 24 hours like they claim, on what I used it, no hope. 10 days later dead plant remains are still visible, maybe on other softer weeds, but tough old dandelions it kill but did not destroy.

Dandelion before.jpg

Dandelion after.jpg

[Whwoz]

A different type of weed growing on the edge of the concrete in front of the shed.

Unk Weed before.jpg

Unk Weed after.jpg

[worth1]

Strange y'all have 4% and 8% where here in the US they have 5 and 10 %.

[Whwoz]

The big test, Kikiyu and cooch, two rhizomatous grasses that have surface/sub-surface runners, Kikyu about 5 or 6mm 1/4 inch thick, cooch about 1 to 2 mm 1/20th an inch thick.

Kikiyu Before.jpg

Kikiyu after.jpg

It has obviously killed the above ground Kikiyu stems where it has come into contact with, but I am not expecting much killing travel through the plant.

So far this mixture would seem to be suitable for use under the conditions it was shown for in the google feeds, that is to kill weeds under conditions where one can saturate the plant with the mix. Small soft plants may collapse in under 24 hours, but not older, tougher plants. Useful in small areas where one does not want to use Round Up or similar herbicides, but of limited use on a larger scale.

[Whwoz]

Strange y'all have 4% and 8% where here in the US they have 5 and 10 %.

Not sure of the actual process used in Vinegar manufacture, but it would be a lactic acid bacterial fermentation using one or more species. Species selected maybe limited by the acid produced, which would then be diluted to a given strength. Why the levels are where they are I have no idea. I understand that in the UK, one can also get "horticultural" grade vinegar of around 24% acidity.

[Cole_Robbie]

A different type of weed growing on the edge of the concrete in front of the shed.

Unk Weed before.jpg

Unk Weed after.jpg

The wide, round leaf weed is plantain. The juice in the leaves will take the pain away from bee stings.

[Whwoz]

A different type of weed growing on the edge of the concrete in front of the shed.

Unk Weed before.jpg

Unk Weed after.jpg

The wide, round leaf weed is plantain. The juice in the leaves will take the pain away from bee stings.

Thanks for that information @Cole_Robbie, very timely as we have just started bee-sitting two hives!

[Shule]

Strange y'all have 4% and 8% where here in the US they have 5 and 10 %.

Not sure of the actual process used in Vinegar manufacture, but it would be a lactic acid bacterial fermentation using one or more species. Species selected maybe limited by the acid produced, which would then be diluted to a given strength. Why the levels are where they are I have no idea. I understand that in the UK, one can also get "horticultural" grade vinegar of around 24% acidity.

Do lactic acid bacteria make acetic acid, too? I know acetic acid bacteria will turn alcohol into vinegar. I'm not sure what will turn sugar and other things directly into vinegar, though.

[karstopography]

Acetobacter Make acetic acid. Lactobacillus make Lactic Acid.Vinegar is acetic acid and water.
Acetic acid is CH₃COOH. Lactic Acid is C3H6O3

[karstopography]

Acetobacter eat ethanol. So Acetobacter rely on yeast to make them something to eat. Basically, it’s all yeast and bacterial poo.

[Whwoz]

@Shule you and @karstopography are correct, 3 am is not always the best time to be on here for me it would seem. Vinegar is two stage process, initial fermentation to alcohol, then fermentation to acetic acid. What strength acidity the Acetobacter can tolerate I cannot recall.

[Mark_Thompson]

I used 30% vinegar from Home Depot the other day. Killed all the broad leaf weeds, some of the grass survived though

[worth1]

One bad thing about it is the weeds come back from the roots many times and it kills living organisms in the soil.

[brownrexx]

I have read that vinegar will only kill the part of the weed above ground which is why I have not used it and I hesitate to use any kind of salt because although it will work, it will prevent garden plants from growing in that area until the salt dissipates and I don't know how long that will take.

I have some Canadian thistle that I tried digging all of last year and yet it continues to pop up in my garden so this year I covered it with some pieces of weed blocking cloth and holding it down with bricks. I am hopeful that this will work.

[NMRuss]

Wow funny... I add vinegar to our high ph soil and I use epsom salts in the soil for the magnesium. Tomatoes and chiles love it.

[worth1]

Wow funny... I add vinegar to our high ph soil and I use epsom salts in the soil for the magnesium. Tomatoes and chiles love it.

Yes I use vinegar in my high pH soil also.
The high pH comes from my high calcium water.
That's why I welcome a good rain.