If you have been looking for a natural way to kill weeds, you’ve most certainly seen recommendations for using vinegar, either alone or in combination with other things.
And it surely sounds both easy and harmless. I mean, who doesn’t have vinegar in their home. And who hasn’t used it for both cooking and cleaning.
And yes, vinegar does kill weeds. But none of these things means that it kills every weed or is a good idea in every situation.
Read on to find out where, when and how to use vinegar in your home garden.
How Vinegar Kills Weeds
The active ingredient in vinegar is acetic acid. It works as a contact herbicide, damaging the plant tissue that it comes in contact with. So if you spray it on the leaves of a plant, you may see those leaves wilt and turn brown fairly quickly.
This also means that it’s indiscriminate – it doesn’t know the difference between a weed and a plant that you want to keep in your garden. So if you are spraying a weed, that spray may splatter onto other plants and kill them as well.
Because of how it works, vinegar works best on young plants. When you try to use it on well-established perennial weeds, it can kill the surface foliage but it may not completely kill a weed with an established root system. And that weed may shortly re-appear.
Stronger is not Necessarily Better
It may be tempting to turn to horticultural vinegar rather than simply household vinegar.
Household vinegar is around 4-6% acetic acid. Products sold as horticultural vinegar are upwards of 20% acetic acid. Well, isn’t that better you might ask. It should kill more weeds, right? And while that higher concentration may do more damage to weeds, it also makes it more dangerous for you to handle. It can cause serious injury to your skin and eyes. If you do decide to go this route, be sure to read the package directions very carefully, wear the correct protective equipment and follow the directions carefully.
What About the Vinegar, Salt and Dish Soap Solution I See Recommended On-Line?
Personally, I would skip it.
Penn State recommends against homemade herbicide mixtures because household products are not necessarily formulated, tested or recommended to be combined or used on plants.
Salt specifically can injure plants you want to keep and can build up in the soil which is not something you want. Remember, ‘natural’ does not necessarily mean harmless.
Where Vinegar Can Be Useful
Vinegar can be useful in very specific situations. It can work well on young weeds that are growing in places like cracks in sidewalks and driveways, in gravel areas, or other areas away from plants you want to keep.
Where I Would Not Use Vinegar
I would not make it my primary method of weed control in flower beds or vegetable gardens. As we discussed before, spray can get on the leaves of these plants and kill or damage them. And repeated applications can change the soil pH and have detrimental effects on both plants and beneficial organisms in the soil.
The Bottom Line
Vinegar can have its place as one of your options for weed control but not as the only method. Used sparingly, carefully and in the right situation, it can help to make weed control easier and more efficient.
