Conclusion. The 20-30% horticulture grade acetic acid is an effective herbicide that can be used by organic growers to replace glyphosate, but will require more retreatments through the season. The 5% acetic acid was not as effective.
The acetic acid in even household vinegar was MORE toxic than Roundup! Going one step further, in this case a comparison of rate of application is a moot point. A 1% solution of glyphosate will kill most any annual weed listed on the label, and also the majority of perennial weeds.
Vinegar is acidic and will eventually kill most broadleaf weeds, but the acid will kill the leaves before reaching the root system, and the weeds may grow back quickly.
In concentrations this strong, vinegar becomes hazardous and can cause environmental damage. Vinegar is a contact or "burndown" herbicide, killing what it touches within hours or days. The worst part is that it may looks like it's working, but weeds will then resprout from the roots, particularly perennial species.
You can up its efficacy by adding a cup of table salt and a tablespoon of liquid dish soap to a gallon of white vinegar. Usually, this mixture only kills the tops of the target weeds, leaving the roots that can regrow new shoots.
The main ingredient in natural organic homemade weed killer is apple cider vinegar. Apple cider vinegar includes acetic acid, which kills weeds. As the apple cider vinegar mixed in water, this solution will effectively kill weeds.
Organic Roundup alternatives include herbicidal soaps that use fatty acids to kill weeds and industrial vinegar, which contains much higher levels of acetic acid than what you have in your kitchen. Acid-based herbicides burn down some young weeds. Corn gluten meal can kill grass weeds and broadleaf weeds.
Spraying a little white vinegar onto the leaves of weeds can keep them under control as well. Grocery store vinegar will do, but more acidic vinegar is also available at your local home and garden store. You can also combine a little rock salt with the white vinegar for added weed-killing power.
Ordinary distilled white vinegar with 5% acidity is cheap and works great. If you can find a higher acidity, even up to 20%, it is going to work faster, but the end results will be the same.
What natural weed-killers kill weeds down to the roots? Boiling water and flaming will kill the roots of weeds. Vinegar kills roots, but it may take a few days for the roots to die off after the vinegar solution is applied.
Vinegar is a contact herbicide; that cannot get to the roots of weeds to kill them. This pesticide is most effective when applied on a warm day. Reapply herbicide to older and more established weeds to keep them from re-growing. Reapplying will weaken the weeds, eventually killing them.
Vinegar with a higher concentration of acetic acid tends to control weeds more effectively. Household vinegar is generally 5% acetic acid. Some herbicidal vinegar products are 20% or 30% acetic acid. In general, 20% or 30% acetic acid is more effective because it more completely kills young leaves and growing points.
White vinegar is considered one of the strongest weed and grass killers, thanks to its relatively high acetic acid content. This chemical removes the moisture from weeds, killing them via dehydration, and is even more effective when mixed with a bit of dish soap to break down the plant's outer layers.
Even though vinegar is an acid, it breaks down quickly in the soil and, therefore, is not likely to accumulate enough to affect soil pH for more than a few days. Vinegar causes a rapid burn to plant tissue of susceptible species, so unintended injury is quite likely without knowing more information.
Adding ammonium sulfate (AMS) to the water in the spray tank before adding glyphosate will act as a water conditioner and improve weed control, regardless of whether or not a surfactant is needed.
It can persist in soil for up to 6 months depending on the climate and the type of soil it is in. Glyphosate is broken down by bacteria in the soil. Glyphosate is not likely to get into groundwater because it binds tightly to soil. In one study, half the glyphosate in dead leaves broke down in 8 or 9 days.
Glycosulphate is the strongest weed killer chemical on sale and will kill grass too, but most gardeners won't need a product this strong as more targeted chemicals are nearly as effective.
Roundup is banned in more than 20 countries because the herbicide has been linked to an increased risk of non-Hodgkin lymphoma and other types of cancer.
Avoid spraying weeds if the wind has picked up ahead of a storm, or in any particularly breezy conditions. Wind can cause the herbicide to drift and cause damage to plants you don't plan on killing.
A bottle of household vinegar is about a 5-percent concentration. Canada thistle, one of the most tenacious weeds in the world, proved the most susceptible; the 5-percent concentration had a 100-percent kill rate of the perennial's top growth. The 20-percent concentration can do this in about 2 hours.
Yes, it's true…vinegar does kill weeds, especially when used along with dish soap. Dish soap, vinegar and a spray bottle are all you need for making your own weed killer. The acetic acid in vinegar “sucks out the water” from the weed, which dries it up.
Combine four parts vinegar to one part water. Add about an ounce of dish soap to a gallon of the mixture. Mix well in a spray bottle or other container (if you are not spraying the mix).