Experts and BHG readers answer.
A quick search of the web for homemade deer repellent will get you dozens of recipes, some of which may be effective, and some which may not be terribly effective. Most contain eggs (their sulfur content is a smell repellent). Other common ingredients are soap, garlic, cloves, dish detergent, ammonia, and hot sauce. All of these products have some deterrent effect. We do not have a homemade recipe for deer repellent that we have tested or that we can recommend.
There are several commercial deer repellent products that are all natural and moderately priced. You may want to consider Messina Wildlife Control or Liquid Fence.