Can vinegar kill weeds? Yes, it most certainly can.
But there’s a little bit more to it than just taking a bottle of vinegar from your kitchen and using that in the garden.
Here’s the scoop.
Vinegar is an acid, also known as acetic acid. It works as a contact weed killer, and will kill anything that it comes in contact with when you spray it on. It’s not a poison though. It burns up the plant. So it might not completely kill woody, established plants. But it typically does well on weeds. It works best when applied during higher temperatures, and when there is direct sunlight on the weed.
Since it is a contact killer, you have to apply it carefully. If you spray it all over the grass around the weed, you’ll end up with a brown patch in your lawn.
Using regular red or white vinegar from your kitchen is often not effective at killing weeds. Vinegar for cooking is diluted, and is typically only 5 percent acetic acid.
The most effective type of vinegar for killing weeds is 20 percent vinegar. But you have to be very careful if you use 20 percent vinegar, because it is an acid that can burn your hands and eyes. You don’t want to spray it from downwind, where the spray gets in your face. If you do get it on you, you’ll want to wash off your hands or skin. I’ve gotten it on my hands before, and there was a slight burning sensation, but nothing too scary or serious. I imagine that it would really hurt if you got it in your eyes or on your face though, so you’ll want to avoid that.
There’s some kind of an EPA rule where you have to register vinegar as a pesticide if you want to sell it as a weed control product. So if you ever see it for sale, it’s unlikely that the bottle will mention anything about weed control or how to use the product.
Weed Pharm is a 20 percent vinegar weed killer that is registered as organic, and suitable for weed killing.