How to – For this recipe, all you need is vinegar of some kind, salt, and soap. The soap helps cut through oils the plant’s leaves have as protection, and the salt and vinegar dry out the plants to kill them. There are variations and substitutions that can be made, and I’ll list those below. For the recipe, you’ll need: 1-gallon white vinegar 2 cups Epsom salt 1/4 cup Dish soap (Castile soap can be used for a more natural option) To make the homemade weed killer, combine the ingredients in the order listed in a large garden sprayer. Replace the lid on the sprayer, and gently mix the ingredients by shaking and swirling. You don’t want to shake it so vigorously that the soap foams too much. Pump up your sprayer, and wet the weeds with your homemade weed killer solution. You should be able to see a difference within 8 hours of spraying the homemade weed killer.