Deer repellents are a popular way to control deer damage for homes, gardens and small commercial crops. Repellents discourage deer browsing by making plants less appetizing or by containing an odor that deer avoid because it triggers an alert that a predator may be nearby. They both have varying degrees of success. Rotating both types of repellents or combining them may improve their success. Deer repellents should be applied regularly, especially after a rain.
Repellents that have a sulphur odor seem to work best. Tests showed that repellents that contained eggs, garlic, predator urine or animal by-products seemed to be the most effective. The theory is that if it smells like something died nearby, then there's probably a predator nearby. People have used human hair and urine as a repellent, but that won't work if the deer are used to living in close proximity to humans. Products that also contained peppermint and cinnamon seemed to get the best reviews.
Most deer repellent products contain putrescent whole egg solids. Research indicates that of the active ingredients, a ratio of at least 20% putrescent whole egg solids seemed to be the most effective ratio as a deer repellent. Putrescent whole egg solids aren't really rotten eggs. These are just eggs that are deemed inedible for human consumption either due to imperfections or damage, such as cracked shells.
DIY Homemade Deer Repellent Concentrate
4 eggs or 4 TBSP sulphur powder 2 tablespoons Tabasco sauce or cayenne pepper 2 tablespoons garlic powder 1/2 tsp each peppermint and cinnamon (essential oil) 1 tablespoon vegetable oil or castor oil 1 teaspoon liquid dish soap Let the mixture steep for a few hours (preferrably overnight) If you'll be spraying it, strain the mixture and pour into a one gallon garden sprayer and add enough water to fill sprayer. If you're using it on polytape fencing, add the mixture to a gallon bucket, fill with water and then soak the polytape in the bucket for several hours before installation. For more information on using a polytape for perimeter control, visit the Nuisance Deer page. Always test the mixture on a few leaves before spraying the entire plant or shrub. If you'll be spraying onto new growth or sensitive foilage, leave out the essential oil and vegetable/castor oil and test a small area before application.
DIY Deer Repellent Ingredients
Here are links to the ingredients used to make the DIY Deer Repellent
Deer Repellent Products
And here are links to deer repellent products, just in case you'd rather not DIY.