The University of Illinois Extension School recommends Havahart's Deer Away Big Game Repellent
, a powder that contains a high concentration of smelly egg solids to target sense of smell. Also on the market: Deer Off
, a spray product containing capsaicin that deters predominantly by taste, and Hinder
a spray of ammonium salts of higher fatty acids creates an odor barrier. Reapply repellent after rainfall, and use a different formula from time to time to protect plants and prevent deer adaptation. Coverage should start from the ground and extend upward six feet.