One natural dog deterrent spray can be made from vinegar and water, according to The Nest. Clear vinegar such as white vinegar mixed with five parts water will create a sour odor to which dogs' noses are sensitive.
Other options for natural dog deterrent sprays use citrus oil and rubbing alcohol, says Gardening Know How. Use drops of citrus-scented essential oil in a spray bottle filled with water around the house, or apply the oil in drops directly to furniture. Dogs are repelled by citrus smells, and will also avoid areas of a yard that have been sprinkled with chopped orange or lemon. Alternatively, mix rubbing alcohol with two parts water and use this as a spray deterrent. This spray should not be used on plants, as it will severely damage them.
Cayenne pepper is the key ingredient in another natural dog repellent spray, notes Buzzle. The recipe is one part cayenne pepper to 10 parts water. Cayenne pepper can harm dogs' sensitive noses, so it's important not to make the mix any strong than 1:10. The spray works by slightly irritating the eyes, nose and throat of dogs. Alternatively, add cayenne pepper to a pot of potpourri and keep it near furniture to protect it from the dog.