Salt and vinegar mixed together form a solution that is deadly to all vegetation. Weeds are killed or weakened and if exposed your lawn suffers exactly the same fate. Concrete sidewalks crumble with longtime exposure to salt and vinegar. Used properly, salt and vinegar kill weeds without killing grass and plants. The different formulas for the salt and vinegar solution are designed to address specific problems and care must be exercised when using them.
Small Patch Weed Killers
Pour the solution of 1 qt. boiling water, 5 tsp. white household vinegar, 6 tsp. salt, 2 tsp. liquid dishwasher detergent and 3 tsp. lemon juice into a large hard-plastic pitcher with a narrow spout for precise targeting. The roots are the primary target; use a hand-held lawn aerator to plug holes around the weeds to get the chemical solution closer to the roots. The combination of boiling hot temperature and chemical makeup kill weeds.
Large Patch Weed Killer
Make a solution of 1 qt. household white vinegar, 3 tbsp. salt and 1 oz. of liquid dishwasher soap. Mix until the salt is thoroughly dissolved. Use this solution in a spray bottle on patches of weeds that are small yet worrisome. Use it in a garden pump sprayer for concentrations of weeds. Do not use it where it will drift onto healthy grass or plants. The salt in the solution is toxic to vegetation but will wash away after several rains or waterings and for this reason a repeat application is probably necessary.
Strong Weed Killer
Combine 1 lb. salt with one gallon of 5 percent white vinegar and mix until the salt is dissolved. This solution sterilizes the soil until rain and sun degrade the salt content. The solution kills weeds in sidewalk, driveway and parking lot cracks. It corrodes concrete and is best applied by a nozzle narrow enough to pour a stream the width of the crack. This spray is also used on large areas where there is no concern for surrounding vegetation. Use safety goggles and chemical-resistant gloves.
Potent Weed Killer
Use this weed killer recipe very selectively. It is lethal to vegetation and depending upon the weed infestation is applied by several different methods. The recipe begins with one gallon of 10 percent white vinegar which is approximately twice as strong as household vinegar and is available at garden centers, 1 oz. of orange oil, ½ cup rock salt and 1 tsp. liquid dishwasher soap. Orange oil is very acidic, and the liquid dishwasher soap while also toxic to vegetation also acts to distribute the solution over the plant. For small stubborn weed patches pour the solution directly on the weeds with a plant watering pitcher.