Certain acid-loving plants can thrive by being given a mixture of white distilled vinegar and water occasionally. Some acid-loving plants are azaleas, gardenias, hydrangeas and rhododendrons.
Mixing 1 cup of vinegar to a gallon of tap water and watering these acid-loving plants can give them a little boost. Vinegar can also be used as a nonselective herbicide, so take care as to where and how it is sprayed. Always dilute it when using it to water plants. Vinegar is also helpful in decreasing the pH in the soil, increasing the acidity level.
Spraying vinegar around a garden can help to deter cats and some other critters as they dislike the smell. This can also work for ants and slugs.