Natural weed killer recipe - Combine 2 cups of vinegar with ½ cup table salt in a spray bottle, add a dash of liquid dish soap to it. Mix well to dissolve the salt. Set spray nozzle to "stream" rather than "mist" and aim for the base of the weed. Spray on a hot sunny day, avoid spraying on windy days as it can kill plants too. Your weeds will usually die within a week, if not, reapply.