A vinegar based weed treatment can be used in gardens and for lawn maintenance for weed control of many broadleaf weeds. As an organic herbicide, vinegar is non-toxic to animals, has no residual effects, and does not build up in the soil. Many tests have been done showing that vinegar and vinegar mixtures, when applied correctly, can burn back or completely kill many garden and lawn weeds. As home made remedies for weeds go, vinegar is cheap, easy to use, and quick to work, making it a good choice as an organic weed killer.
There are some misconceptions about using vinegar to kill weeds that need to be understood. Being an acid, vinegar can lower the soil pH, but the effect is only temporary with the soil returning to its previous balance within a few days. Vinegar, unlike many commercial herbicides, is not systemic, meaning it will not travel through plants to kill their roots and will only affect the areas where it is applied. Vinegar sold for kitchen use is usually a 5 % solution and is generally strong enough for use as a weed killer. Stonger vinegar solutions, 20 % and higher are available, but like all strong acids, they can be dangerous to the user and harmful to the environment. Vinegar by itself can be used to burn back or kill many weeds, however mixing it with other additives can increase its power and usefulness. Vinegar herbicides work best on young tender weeds with older established weeds often requiring repeated applications before being killed. Most grassy weeds will not be well controlled using a vinegar based herbicide. Vinegar sprays work best when applied to weeds in the full sun and during hot weather.
Additives to use in a vinegar based weed treatment include dish washing soap, and rubbing alcohol, with salt often being cited in many recipes for organic weed killers. Salt however, while a good weed killer, is not good for the garden or lawn. It will build up in the soil and spread to surrounding areas, making them toxic for nearly all plants. Add 4 tablespoons of liquid dishwashing soap and 1/2 cup of rubbing alcohol to a gallon of white vinegar to make a good strong organic weed killer. Store the weed treatment mixture in a well marked and tightly sealed plastic container, in a cool dark place. Mark it as poisonous because of the rubbing alcohol it contains. To use the vinegar weed treatment, pour some into a spray bottle or garden sprayer and spray the weeds just until the leaves are wet with the solution. Tender weeds such as clovers, plantains, chamber bitters, young crab grass, and young dandilions should turn black within an hour and be killed completely. Tougher weeds such as thistles, ragweeds, older dandilions with taproots, and pigweeds will require several treatments for full control. By spraying these weeds before they bloom and set seed, it is possible to gradually get rid of them on a piece of property. Watch for weeds to resprout after being sprayed and respray the new growth once it appears. By keeping tough weeds from growing new leaves it is possible to kill the roots by starving them out.
This vinegar weed treatment is a non selective herbicide and will damage any plant it gets on, however because it is not systemic and will not spread throughout the plant, this organic herbicide is fairly safe to use around desireable plants. Only the leaves it is applied to will be damaged and since it leaves no residues, it is a safe organic garden herbicide. New garden transplants can be set out right after using this vinegar weed killer without harming them. Be sure to wash out any garden sprayers after using them with this mixture as it can cause metal parts to rust. Be careful not to get it in the eyes. Using vinegar as a weed treatment product is a great way to cheaply handle garden weed problems and lawn maintenance.