Answer: Deer can leap over very high fences to get at a garden so you need one at least 8' high to keep them out. Some folks even put a bit of fencing flat on the ground around the perimeter under the theory that deer don't like walking on it, I suppose it is aggravating when they get their hooves in it.
Sprays of egg solids, hot pepper oil and other such ingredients are available and may help some, especially when the deer "pressure" is not too high. Human hair (from the local barber shop) in bags made of hosery and perfumed soaps have worked for me when they had other options to feed upon.
Hope these suggestions help you keep the local wildlife from consuming your garden!
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