If you are looking for an all natural weed killing solution to control your weeds using vinegar and salt, there is a lot of information on the internet as well as YouTube that will state that using vinegar and salt to kill weeds is effective.
And it is....to a point. If you do a search on YouTube, for example, you will find many videos showing you how to mix the vinegar and salt and how to apply it. Those videos will also show you the results of their tests and yes, the weeds are wilted and appear to be dying.
They, in fact, are. So how can you dispute the claims that the all natural vinegar and salt weed killing solution is an easy and cheap way to control weeds. The answer is simple. Do a search on YouTube regarding the vinegar and salt weed killer recipe follow up video.
There are none. And the ones that do address it show you what happens to the weeds a week later. You'll be shocked at the results. But I will spare you the effort. What those follow up videos do show is that the weed that appeared wilted and dying immediately following the application of the vinegar and salt solution are far from wilted and dead.
The weeds look as healthy as they did prior to the so-called homemade vinegar and salt weed killer application. That is why there are no follow up videos from the channels that use this weed killing solution. It is, at best, a very short term solution to control weeds. This article will explain why the vinegar and salt solution fails as a weed killer and why we do not recommend it.
The Vinegar and Salt Weed Killer Doesn't Really Kill the Weed
After the application and for a day or two you may think this article is wrong. My suggestion is that you wait a couple of more days before you come to that conclusion. The reason the vinegar and salt solution doesn't kill the weeds has to do with how herbicides work. You have two general categories of weed killers: a contact one and a systematic one. According to the Penn State Extension:
Contact herbicides kill only the plant parts contacted by the chemical, where-as systemic herbicides are absorbed by the roots or foliage and translocated (moved) throughout the plant. Herbicide activity can be either selective or non-selective. Selective herbicides are used to kill weeds without significant damage to desirable plants. Nonselective herbicides kill or injure all plants present if applied at an adequate rate. source
To be an effective herbicide, it must do four things effectively in order to kill a weed:
- adequately contact plants
- be absorbed by plants
- move within the plants to the site of action without being deactivated
- reach toxic levels at the site of action
To be sure, when you spray the vinegar and salt solution on a weed, the visible part of the weed will die. But, in a few days the weed will reappear because the vinegar and salt solution doesn't perform effectively the requirements for a herbicide.
Specifically, the vinegar and salt weed killer will make contact with the foliage of the weed. The PH levels of the vinegar will basically burn the foliage and will kill it. However, the vinegar and salt solution does not transfer from the foliage to the entire plant (i.e. roots). Thus, although you have killed the visible part of the weed, the weed's roots are fully intact and will produce additional foliage to replace the ones that were killed. The vinegar and salt weed killer is not a systemic weed killer and thus it does not actually kill the weed in its entirety.
In other words, it will grow back in a couple of days. That is why there is never a YouTube video that shows a follow up to the application a week later. The best you will find is one or two that will show you a couple of days later, but none beyond that point. The all natural vinegar and salt weed killer simply does not work if you are looking to kill the weed completely so it will not grow back.
Adding Baking Soda to the Vinegar and Salt Weed Killer Makes No Difference
Another popular weed killing recipe is adding baking soda to the vinegar and salt formulation. Baking soda has many beneficial uses and it performs great in mouthwash, it's great for whitening your teeth, it even makes for fantastic deodorant, but, as a weed killer, it's lousy.
As Ann Barnes from the NC State extension states on the Durham Master Gardeners website:
One website I saw touting baking soda as a weed killer claimed that “baking soda neutralizes the pH of soil and nothing can grow there”. Another claimed that “sodium bicarbonate is deadly to weeds”. First, the pH claim is ridiculous. Most plants grow best in slightly acid to neutral soil (pH 6.0 – 7.0). Our NC soils tend to be more acidic than this, so adding baking soda could conceivably raise the pH to a more beneficial level, not to a toxic level. Garden lime is a more effective way to raise the soil pH than baking soda. As far as being deadly to weeds – I would speculate that it works in a similar fashion to the previously mentioned home remedies – by desiccating foliage but not killing roots. source
Baking soda will kill the foliage of the weed, just like the vinegar and salt solution will, but just like the outcome of that solution, the weed is coming back in a couple of days. Additionally, Ms. Barnes concludes in her article, "To summarize: while any of these remedies might provide some temporary weed control, your best natural, organic weed killer would have to be your own two hands. I’m afraid there’s just no substitute for old fashioned hard work if you would prefer not to use chemical weed killers."
Hopefully by now you are convinced that the vinegar and salt solution propagated throughout the web as well as on YouTube as almost a miracle DIY, homemade, all natural weed killer claim doesn't hold much weight. As a weed killer its highly ineffective.
Think about this: if you paid a commercial lawn care service to come out to spray your yard to get rid of weeds and they did spray and the weeds looked dead but came back two days later, what would you say? You would call them up and ask for your money back.
You would say it didn't work. Well, that is exactly what the vinegar and salt weed killer will do; after the initial application, the weeds will look dead, but two days later, though, the weeds will be back. So save your money and time. If you are adamant about not using a chemical weed killer, you need to go to your local big box store and buy a great pair of work gloves.
If you are willing to use a chemical weed killer, you have many options to choose from that are highly effective and will save you hours of hard work.
UPDATE: I couldn't resist but to do a search on YouTube to provide you with some actual follow up videos of people who put the vinegar and salt weed killer claim to the test. Here is a great video that totally disproves any claim that the vinegar and salt weed killer is effective: