The Effects

• Vinegar has the ability to kill weeds -- and in some cases prevent them from growing back -- due to the acetic acid within it. Most store brand vinegars have 5 percent acidity, which means they contain 5 percent acetic acid. Some vinegars contain between 10 and 20 percent acidity. The more acetic acid within the vinegar, the more powerful a weed killing solution it becomes. Younger weeds sprayed with vinegar may not grow back due to a lack of sufficient reserves. Older weeds sprayed with vinegar will grow back, but in a weaker state. Older weeds will eventually die and not return if they are sprayed on a regular basis.
  
  

The Vinegar Solution

• There are numerous homemade weed killing formulas, all of which contain vinegar as the primary ingredient. Some recipes consist of vinegar, salt, soap and water, others vinegar salt, soap and no water. In some cases, vinegar alone is used. One recipe uses 1 oz. of dish washing soap per gallon of vinegar. Some weeds such as crabgrass may grow back and require repeated applications.
  
  

Considerations

• While vinegar can be used to kill weeds -- at least for a period of time -- the acetic acid doesn't only target weeds. If a vinegar solution comes in contact with any vegetation within a garden, that vegetation will also die. Be careful where you spray. Make sure to use tight, controlled bursts when spraying so that the vinegar does not come in contact with vegetation you wish to keep.
  
  

Warning

• If you are using ordinary vinegar -- or vinegar which only contains 5 percent acetic acid -- you should not have much to worry about if it comes in contact with your skin. However, stronger solutions -- such as the 10 or 20 percent acetic acid varieties -- can cause a burning sensation if it comes in contact with your skin. If using this formula, always wear gloves to protect your hands. Wear a face mask and goggles to prevent the vinegar from getting in your eyes.