Keep deer away from plants by introducing unpleasant smells, adding noise deterrents, building fences and growing plants deer don't like. A combination of deterrents is generally needed to prevent deer from eating garden plants.
Blood meal is a non-chemical powder that can be sprinkled around the garden to ward off deer, which find the smell unpleasant. Other smells deer don't like include rotten eggs, processed sewage, mothballs, garlic and soap. Make the garden smell like a human to scare deer. Try human hair, bar soap or cologne.
Whistles, flags, noisemakers and even pots and pans make noises that scare deer. Use twine or fishing line to place various noisemakers around the garden, or set up a triggered system that includes flashing lights, noises and sprinklers when deer enter the garden.
Some deer can be deterred only by fences. An electric fence provides a mild shock when deer try to cross it. Build a fence 8 feet high to prevent deer from jumping over it, or try two shorter fences a few feet apart. Shrubs or bushes around the fence preclude a good takeoff or landing site for jumping deer.
Deer avoid entering gardens populated by plants they don't like. Try rosemary, salvia, asters, black-eyed Susans, irises, mountain laurels, burning bushes, butterfly bushes, Japanese maples and cedars. Deer dislike the smell, taste or feel of these plants and generally avoid them. Planting some of these plants around the border of the garden can be effective as well.