A natural squirrel repellent is a natural (as opposed to chemical) substance that deters squirrels from approaching an area. Squirrels do not like hot and spicy foods, so sprinkling cayenne pepper in the garden can be an effective deterrent. For the same reason, a solution of diced jalapeño peppers, vinegar and water also works.
Squirrels hate the scent of peppermint. Planting peppermint around your garden may keep squirrels away. Placing a few drops of peppermint oil on cotton balls and dispersing them throughout your garden helps keep squirrels from feasting on garden plants.
Another option is to sprinkle the urine of squirrel predators around the garden. Wolf urine may be ordered on the Internet for this purpose. Lastly, consider enlisting the help of common squirrel predators, neighborhood cats. By putting out a saucer of milk or strategically planting catnip, you attract cats to chase away squirrels.