The Vinegar Question

The Vinegar Question

I get the vinegar question a lot.   “Does that stuff work like you say it does?”  When I start telling people to use a 10 percent vinegar solution instead of synthetic herbicides to control weeds, I get some really interesting looks.  Most people nod, grin, and give me that “Yeah, Right” look. 

Let’s understand; I’m not talking about your run of the mill grocery store white vinegar.  What is sold in the market is 5% distilled vinegar.  While it is the same stuff that I use routinely around my yard and garden, it is less concentrated.  If you try it, you may see some discoloration on the leaves of the plants you spray, but it won’t have the dramatic effects I am about to show you.

Horticultural Vinegar

The vinegar I buy and use in my landscape is 20% horticultural vinegar.  Horticultural vinegar is much more concentrated than what is usually available in your local market.  You must respect this higher concertation.  Horticulture vinegar is acid.  It can cause serious irritation of the skin, ruin clothing, and damage your eyes seriously if it splashes.  Use all the cautions.  Wear proper clothing to protect your skin when you work with it.  Wear rubber gloves.  Protect your eyes with goggles.  A little practical safety goes a long way.

Mixing and Spraying

I mix my vinegar down to a 10% solution.  Mixing is a simple procedure.  I put a gallon of rainwater in my tank sprayer, add about a half a cup of liquid dish soap as a surfactant, and then empty the gallon of horticultural vinegar into the sprayer.  I cap the sprayer and shake gently to mix everything thoroughly.

I set the spray tip of my wand to produce a relatively fine mist.  I want to completely coat the leaves of the plant while localizing the spray.  I am spot spraying, not broadcasting.  I then keep the tank pumped up, put the tip of the wand close to my target plant, and give it a squirt.  Coat the leaves.  You will get a bit of overspray which will affect your turf.  I try to spray early in the morning before any wind gets up.  I also try to choose a hot, sunny day.

How it Works

Vinegar is not a systemic poison like most of the commercial herbicides.  It doesn’t kill the roots of the plants directly.  The acid burns the green foliage away.  The loss of the green leaves forces the living parts of the plant to use the stored carbohydrates in the roots since there is no more chlorophyll filled leaves to produce those carbohydrates.  During the growing season, weeds don’t store a lot of carbohydrates so you can eventually starve the plant.  Some weeds will wither and die almost immediately.  Others, with more substantial root systems, may take several applications.  Treating Bermuda grass can be a challenge as it has such an extensive root system that burning off enough of the surface leaves to get the necessary effect is difficult.

My Experiment

I decided to conduct an experiment and document the effects of vinegar on my lawn.  I have not sprayed any synthetic chemicals on my yard for several years.  This winter, I didn’t do any weed control, not even the organic treatments which left me with a laboratory of West Texas turf weeds.  I have had everything from clovers to rescue grasses.  At one time, I counted 14 different species of grass and weeds, including some wildflowers in my Bermuda turf.  I chose to keep it mowed and let it grow.  It was green.  The bees had a heyday on the flowers.

I chose a spot for my experiment on the south side of our corner lot, behind a large Eldirica Pine.  There is a small berm on that side of the yard that I put there to keep cars from making it to the corner of our house.  It has been a place that has been difficult to keep grass growing and a mecca for weeds.  Yesterday morning I chose my test area and took some pictures.

Hour One

This shot shows the top of the berm looking north.  You can see that there are patches of Bermuda grass, but there are also a large number of weeds.  Among them, you can see dandelions, henbit, London rocket, purslane, spurge, ragweed, thistle, and rescuegrass.

The Vinegar Question

This picture is a bit closer and you can see the thistle, spurge, and wood sorrel. I  mowed this area the day before I sprayed.

I spot sprayed these areas with the 10 percent vinegar solution and waited for an hour then took these pictures.

Hour Two

The Vinegar Question

This is the same view looking north on the berm.  Notice that the areas that I spot sprayed are already starting to brown and curl.  The Bermudagrass around the areas that I spot sprayed is already starting to yellow a bit. 

The Vinegar Question

This is the same view as the close up above.  You can see on the left of the picture a bit of careless weed that I left unsprayed for comparison.  To the left of the bright green plant, you can see the thistle, ragweed, spurge, and careless weeds that I did spray.  In an hour, they are noticeably stressed and discolored.

I waited for another hour and took another series of photographs.

Hour Three

Again, the top of the berm after two hours.  Many of the weeds are brown.  The bermudagrass is quite yellowed and burned.  It is obvious that the plants I sprayed have been affected quickly by the vinegar.

The Vinegar Question

This is the same area I showed you above.   The unsprayed care
less weed is near the left center of the picture.  In comparison, you can see the other areas that were sprayed and the effect that the vinegar has had In only a few hours.

Hour Four

Another hour and looking back up the berm to the north.  It doesn’t look much different than the last pictures an hour previous.  The weeds that I sprayed are all looking quite brown and limp.  The bermudagrass is yellowed but only on the portions that got a full coating of the spray.  Since the vinegar does not enter the plant’s system, it does not affect the roots of the rest of the plant.  The turfgrass will recover quickly.

Four hours into the spray and showing a wider view of the area with the unsprayed control plant.  You can see in the upper left corner the areas that I carefully spot sprayed.  The bermudagrass is showing little effect, but the weedy plants are withering rapidly.  Around the control plant, all the weedy plants that I sprayed are browned, burned, and limp.

In Summary

I think this series of photos illustrates well my point.  Vinegar, when used properly, is a very effective weed control agent.  It is environmentally safe and leaves no harmful residue.  It can be safely sprayed around the base of trees and woody shrubs. 

I don’t routinely spot spray errant weeds.  It is easier to remove them by hand.  This year, because of my neglect, the lawn had become heavily infested, so I chose to begin a regiment of spot spraying with vinegar.  A day or two after I spray the vinegar, I follow up by spraying the bermudagrass with a compost tea mixture made from compost tea, dry molasses, and worm castings.  I dilute the concentrate compost tea at a rate of 4 ounces per gallon of water.   I spray it as a foliar fertilizer.  You can also mix it and pour it as a drench.  This gives the turf grass around and in the areas that I spot sprayed a little extra boost to recover and fill in the bare areas. 

Near Term

I may have to come back and retreat some of the areas.  I am not the most skilled spray operator, and my spot spraying tends to be hit or miss.  I don’t add dye to my sprayer.  I can’t abide the mess it makes and usually get more on me than I get on the areas I am spraying.

The Vinegar Question – It Works!

Vinegar works.  To be effective, it should be part of a total organic landscape management system.  You need to be working to build your soil health more than anything else.  Healthy bio-rich soil will result in thick, lush turf grass that resists weeds and other pests and disease.  Mow properly at the proper height, mulch your clippings back into the lawn, and water appropriately.  Organic turf management is not difficult, but it does require attention and consistency.

I will be posting followup pictures as I continue to treat this portion of my lawn to see how long it takes Bermuda to re-establish and how well the long term effects of the vinegar fair. 

Horticultural vinegar is available from most good horticultural supply stores.  It can be ordered online, as well. 

For more information on my compost tea recipe check out the article on our website at

Our website at www.westtexasorganicgardening also has a wealth of information on organic gardening and landscape management, turf management, and organic lifestyles.

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