Deer-Departed.com and Food.com each feature recipes for making deer repellent. There are many other recipes for deer repellent that circulate online and among farmers, naturalists and others.
For the Deer-Departed.com recipe, mix 3 raw eggs, 3 tablespoons hot sauce and 3 tablespoons minced garlic in a blender with a small amount of water. Add the mixture to a gallon of water. Put this in a spray bottle and use on whatever plants the deer are eating.
Food.com's recipe boasts a five out of five-star user rating, as of 2015. To make it, put 1 gallon of water in a pot. Grate 1 bar of Ivory soap into water. Crush 1 large bulb of garlic and add to water. Add 1 2-ounce jar of crushed red pepper flakes to the water. Simmer on the stove until the soap melts. Remove from heat and cover for about 1 week. Strain mixture through a fine mesh strainer and store in a large jug. This process creates a concentrate that must be mixed with water. The ratio is 1/2 cup concentrate to 2 1/2 gallons of water.
When ready to use, mix the concentrate and water using the aforementioned ratio and spray on the plants or other areas where the deer frequent. An important note: when you need to use the mix again, discard the previous mixture and make a new concentrate and water mix.