Although I avoid spraying if possible, if I'm having a problem with deer eating something, I usually spray Bobbex. If I remember correctly, Bobbex was originally designed as a fertilizer spray and they figured out later that deer didn't like it. I know it does make some plants bigger and more robust than normal when you spray after every rain washes it off. It does smell pretty bad until it dries so hopefully you're not spraying a large area. Made from meat meal, fish oil, putrescent eggs, garlic and other naturally occurring ingredients, according to their website. http://www.bobbex.com/index.htm
I have had good luck with an electric fence consisting of one wire stretched around the yard about 24-28 inches high (I just put it a little higher than my knee). It is turned on by a timer at around dusk and remains on until early morning. I spread peanut butter on it initially every 20-40 feet or in the areas where deer usually enter the yard. A little shock on their nose or mouth seems to deter them, even though they could easily step over or jump the wire. I am fortunate to live with woods around our home. In front where the wire is, I have planted shrubs which partially hide the wire. I use a post that is heavier at the corners and about every 50 feet. Between them at approximate 15 ft. intervals I put a light weight metal rod. I used insulators that are used with electric fencing and painted them with camouflage paint. My transmitter is in the garage and I ran the wires out through that wall underground to the fence. This is easy and effective if you stay on top of it and repair any brakes that occur while the deer are learning about the fence. Check it often and repair right away. We have used this for about 10 years. We live in the midst of lots of deer.
"Plantskydd Deer & Rabbit Repellent is made in the USA from 100% natural, environment-friendly ingredients. Plantskydd Deer & Rabbit Repellent works by emitting an odor that animals associate with predator activity, repelling the animal before it nibbles on plants. Research has proven that odor-based repellents are more effective than other repellent systems where the animal needs to taste treated plants before being repelled. Once animals are attracted to an area and begin feeding, it is more difficult to discourage them from returning. Plantskydd stimulates a fear-based response which will have deer, elk, moose, opossum, and rabbits looking to dine somewhere other than your garden or plantation."
It is blood based, so when you first spray it on it does show up dark, but the color lightens/disappears after a while. It does stay on after it rains.