Keep your hands clean by eliminating weeds with rock salt.

How to Use Water Softener Salt to Kill Weeds

by Jaimie Zinski

Gardeners and homeowners wage a constant battle with an unrelenting foe that pops up at a moment's notice and sullies an otherwise beautiful garden or lawn: weeds. A variety of weed killers are available at your local home improvement stores, but you might be leery about applying these chemicals around your children and pets. According to the University of Illinois, rock salt, a common water softener salt, acts as a desiccant, which sucks out all the moisture from weeds, effectively killing them.

Spread the rock salt on the ground surrounding the weeds. Pay attention while spreading the salt, and immediately pick up any rocks that drop on your lawn, flowers or any other foliage you don't want affected. The amount of rock salt necessary is dependent on the number of weeds. For instance, 1/4 cup of salt will kill a small cluster of weeds, while several cups might be required to kill a field of pesky weeds. Monitor the weeds and reapply one day later to kill any remaining weeds.

Sprinkle the salt over the weeds growing between outdoor pavers or through the cracks in your driveway, patio or walkway. The water softener salt not only kills the present weeds, it also prevents them from growing back for a few months to a few years.

Combine 1 cup rock salt and 1 gallon boiling water in a plastic bucket. Stir the water to dissolve the salt and immediately pour it on the weeds. This is a solution for large patches of weeds, or those not found near any ornamental flowers, your garden or lawn. If necessary, reapply the mixture one day later to kill any remaining weeds.

Combine 1 quart white vinegar and 1/2 cup rock salt in a plastic bucket. Stir the mixture until the water softener salt is completely dissolved. Pour the mixture into a plastic spray bottle and apply directly to the weeds. Watch for any overspray onto neighboring foliage and repeat as necessary to kill any remaining weeds.

Items you will need

  • Rock salt
  • 1 gallon boiling water
  • 1 quart white vinegar
  • Plastic bucket
  • Plastic spray bottle


  • Water softener salt will kill any other plants it contacts, so use it with caution.
  • Rock salt can erode concrete, so use it with caution on your sidewalk or driveway.

About the Author

Residing in Chippewa Falls, Wis., Jaimie Zinski has been writing since 2009. Specializing in pop culture, film and television, her work appears on Star Reviews and various other websites. Zinski is pursuing a Bachelor of Arts in history at the University of Wisconsin.

Photo Credits

  • Hemera Technologies/ Images