There are many smells that are a natural repellent to deer. Most of these fade or degrade over time and need to be replaced every few weeks. Deer will not feed within about three feet of a smell they dislike, so the repellents need to be placed about three feet apart in plants and trees to keep deer from feeding in the area.
Soap: Hang bars of strongly-scented soap from branches of trees or shrubs. Leave the wrappers on to prevent the soap from dissolving from rain or sprinklers.
Fabric softener sheets: Cut the sheets into strips, and hang them from branches
Garlic: Crush or bruise garlic cloves, and hang in bags made of cheesecloth or old nylon stockings
Rotten Eggs: To make a preparation of rotten eggs, combine two eggs with two cups of water and mix in a blender. To make the deterrent more effective, add one to four cloves of garlic and some Tabasco sauce or red chili peppers before blending. Let the mixture sit for several days and then sprinkle it on and around plants. The smell will be less noticeable to humans after it dries, but the deer will be able to smell it.
Hair: Deer are deterred by the smell of human or predator hair. Hair can be obtained from hairdressers or dog groomers. Place the hair in bags, and hang it from trees or shrubs.
Blood meal: The smell of blood is very frightening to deer. Put blood meal in bags and hang around the garden, or simply sprinkle it on the ground around the plants. Blood meal is high in nitrogen and is beneficial as a fertilizer. It can also be spread around the periphery of the garden. The smell is stronger if the blood meal gets wet.
Predator urine: Deer will avoid the area if they think a predator is nearby, and the smell of predator urine is a powerful deterrent. Urine of coyotes, foxes, and bobcats keeps deer and other small animals out of your garden. Predator urine is commercially available either as a liquid or a granular formulation.