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.
As vinegar temporarily changes soil pH, it may be harmful to garden plants and roots so avoid applying too close to those areas (though such an application used just once or twice should be okay).
How Long Does Vinegar Last in Soil? Acetic acid's effect on soil is to lower its pH, which may make it unsuitable for growing some plants. If you were to pour high-concentration vinegar directly onto the soil, the effects could last longer than a month, but that would be an inappropriate use of vinegar as a herbicide.
Beware, though. Vinegar can kill your grass too and, if too much is applied, can make the soil infertile if you put too much in it, so be careful not to spray on your lawn unless you want to replant the grass.
Vinegar is non-selective, meaning it will potentially kill every plant it comes into contact with including lawn grass and other desirable plants.
Increase Soil Acidity
Combine one cup of plain white vinegar with a gallon of water and use the next time you water these plants to see some amazing results. You can also add some distilled vinegar to your soil to fight lime or hard water for other not-so-acid-loving plants.
Due to its burning effects, using vinegar in the garden has been touted as a cure-all for a number of garden afflictions, most notably weed control. The acetic acid of vinegar dissolves the cell membranes resulting in desiccation of tissues and death of the plant.
The most effective homemade option is a mixture of white vinegar, salt, and liquid dish soap. Each of these ingredients has special properties that combine to kill weeds. Both the salt and the vinegar contain acetic acid, which serves to dry out and kill the plants.
Mixing salt and vinegar into a solution may be appropriate for parking lots or gravel driveways, but the combination of the two is difficult to control during application and can damage surrounding plants and soil. It's best to use material other than salt for killing weeds.
Vinegar as a fertilizer: Nope, doesn't work. Acetic acid only contains carbon hydrogen and oxygen – stuff the plant can get from the air. The other things that may be in vinegar could be good for a plant – but it seems an expensive method of applying an unknown amount of nutrition.
Sprinkle 5 tablespoons, or 1/3 cup, of lime over the moist soil around the plant. Water the plant and surrounding soil thoroughly after adding the lime. The lime raises the soil pH and protects the plant's tender roots by neutralizing the effects of the acetic acid in the vinegar.
When equal amounts were given orally and compared, it took less acetic acid to kill rats in the laboratory test that it did glyphosate. The acetic acid in even household vinegar was MORE toxic than Roundup!
White Vinegar:
For it to work, you have to wait for the vinegar to sit in the weeds from your garden for a few days. The vinegar will kill the weed's roots.
Using Bleach to Kill Weeds Permanently
Apply one cup of bleach, undiluted, to the afflicted area. Wait until the weeds turn brown before pulling them out of the ground. Run water around the area to flush the bleach, especially if you are trying to grow plants or grass in that area.
Fruit flies and aphids find the smell of vinegar irresistible. If fruit flies or aphids are a nuisance in your home, yard or outdoor buildings, half fill a small bowl with apple cider vinegar and cover it over tightly with plastic wrap.
Recovery from Vinegar
If you have used vinegar on a plant regularly, it might have increased the acidity of the soil, and will need to recover before you can plant anything else. Raise the pH of the soil by mixing in hydrated lime or limestone and wood ash, especially in the top six inches of soil.
White vinegar and other household vinegars are under 10% acid. When applied to plants, they may burn the foliage but most roots survive and the plant regrows. Horticultural vinegar is approximately 20% acid, highly corrosive, burns everything it touches, and not suitable for household use.
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.
Sodium chloride, or table salt, is also a dessicant. Salt is added to weed killer recipes because it is stronger, and kills some plants that vinegar won't kill. It negatively impacts the soil for a longer period of time than vinegar, and it may affect the roots of other nearby plants, as well.
Vinegar kills most young weeds within 24 hours, so check the area you sprayed during the next 2–3 days to see if they wither away. If the weeds are still standing tall or developing new growth, coat them with more of the vinegar solution. Keep checking and spraying the weeds until they completely die out.
The second reason is that applying vinegar only changes the pH of the water solution in the soil and it does not create a reaction to change the pH of the mineral portion. As soon as you started watering with regular water, the soil pH would soon return to the higher pH.
Diluted fruit vinegar like apple cider vinegar can be an effective high-nitrogen soil amendment for acid-loving plants.