The best thing to protect your garden from deer, woodchucks and rats (yea, rats were eating my tomato's as soon as they got ripe) is a solar electric fence.
Since I use elevated rows and the ground was not level, I put boards in the ground inside the bottom wire about 1/2" away from it so that nothing could get in w/o getting touched. Worked great!
The only other way to get stop woodchucks is to get rid of them. I would catch them in the have-a-heart and bring them in the garage, put a 2X6 in back of it, put my earmuffs on and the 10/22 went to work.