Vinegar

• The U.S. Department of Agriculture has been researching the use of vinegar as a weed killer. Vinegar contains acetic acid and acts as a natural desiccant, which means that it removes moisture from an area. Spraying vinegar on a weed will dry it out and can kill weeds in the span of one afternoon, especially if the weed is in full sun. However, the vinegar will only kill the plant on the surface. The roots will remain intact and new weeds will grow up again a week after a vinegar application.
  
  However, spraying vinegar on young weeds and applying the vinegar on a regular basis can kill weeds at the root. But vinegar does not discriminate between plants. The more vinegar you use in your garden, the more your desired plants will suffer. Only apply vinegar in two-week intervals and only apply vinegar directly to plants you want to get rid of. If vinegar is accidentally sprayed on your desired plants, they, too, will die.
  
  Garden Counselor advises adding an ounce of dishwashing soap to a gallon of vinegar before spraying weeds. Certain weeds have waxy or fuzzy surfaces making them much less susceptible to the affects of vinegar. However, soap breaks down the surfaces of the leaves and helps vinegar cling to the area instead of running off. Also, soap will give the weeds an oily or shiny look so you can be sure where your spray has landed. You will know immediately if any vinegar has made its way onto your desired plants and will be able to wash and save them immediately.
  
  

Salt

• Salt makes soil unsuitable for growing plants and draws water from the area. Salt will kill weeds at the roots but it will also kill your other plants at the roots. However, if you want to get rid of weeds in isolated spaces, such as around your sidewalks or driveway, a small sprinkle of salt at the base of the weed will kill the weed for good. Never use salt in your garden or in liberal amounts. A salted area can stay barren and unusable for two to three months.