The Vinegar Question – Followup

The Vinegar Question – Followup

Following our post about horticultural vinegar a few days ago, a reader posted a question about repeated applications of horticultural vinegar and damage to the soil and the soil biome.  The reader was warned in another group that the use of vinegar was a bad idea, and that spreading the vinegar story is a bad idea. That is a question that needs answering.  Here is the basic answer I gave to that question and some additional information.

The Truth

The Vinegar Question - Followup

The truth is that there are virtually no long term ill effects from using horticultural vinegar on your garden or landscape in the ways we have described. First, vinegar is not a poison; it is an acid. It destroys the green growing part of the plant on which it is applied, depriving the rest of the plant the carbohydrates produced by the chlorophyll in the green leaves. It is not a poison and does not enter the system of the plant. Very little of the vinegar gets to the soil. When it does reach the soil, the bacteria in the soil quickly convert the acetic acid to acetate salts, and then further to their more basic components which integrate into the soil food web. There is no build of up of toxic salts or other synthetic materials in the soil. Which would you rather have on your yard, a naturally produced material that breaks back down to its natural components that came from the food web in the first place or synthetic toxic materials, many of which have known long-lasting carcinogenic effects on humans?

What is Vinegar

To carry this a little further, horticultural vinegar is usually made from grain.  The grain must often used is corn.  The corn is distilled into alcohol and then fermented to create the vinegar.  Horticultural vinegar is usually sold in concentrations of 20% or 30%.   The white vinegar you get at the grocery store is 5%.  Horticultural vinegar is much more acidic than its grocery store cousin and should be handled with caution. 

The Real Question

The real question is what happens in the soil when vinegar is applied to the plants.  If the vinegar is applied appropriately, there is very little happening in the soil.  We advocate spot spraying with a 10% vinegar solution.  If applied properly, very little of the vinegar finds its way to the soil.  What does get to the soil is rapidly decomposed by soil microbes into its basic components; Carbon, hydrogen, and oxygen.  Acetic acids chemical signature is CH3COOH. 

How it Works

Acetic acid works by destroying the growing portion of the plant above ground.  This removes the plant’s ability to create carbohydrates forcing the plant to use stored sugars in the roots.  Once the stored sugars are exhausted, the plant roots die.  Acetic acid is not a systemic weed killer.  It does not enter the system of the plant, so it does not affect plant-eating organisms.  It is in low concentration edible.  We use vinegar every day in our condiments and cooking.  Since it degrades rapidly and is not poisonous, it is a safe alternative to synthetic chemical herbicides.

Some studies have shown the application of vinegar to the soil can increase the number of certain bacteria in the soil.  It also adds carbon and oxygen to the soil as it decomposes.  The net effect is to leave nothing in the soil that has a detrimental effect on soil biology.  Since it is not a systemic poison, it does not migrate through the soil to affect adjacent plants.

A Question of Safety

There are no known medical effects of using vinegar either as a food or as an herbicide.  Every day we hear of another lawsuit or another study that links synthetic chemical herbicides and pesticides with medical issues, including cancer.  Many of the studies indicate that the residuals of these toxic synthetic materials are as medically dangerous as the material itself and can linger in the soil for months if not years. 

It is a Choice

My personal view is that there is no downside to using vinegar in the garden or landscape.  It takes no more attention to safety that should be used if spraying synthetic chemical herbicides and pesticides.  It has no residual effects and is safe for humans and pets.  Despite what others may say, I feel that vinegar is a much better solution and the only real option in an organic systems approach.  I suspect, and this is purely my opinion, that much of the derision spread about vinegar comes from the chemical industry. 

For more information about organic landscape and garden maintenance, visit our website at

Please follow us on Facebook, @westtexasorganicgardening