I have just read Ruth Stout's Garden Mulching book.(1971) and I am going to do it. How to keep snakes out?

I have a 60 x 50 new garden and have put two rolled bales of hay (about 1400 lbs) on the garden for the winter - and around what I had planted. After stopping to think about this situation, I am on a mountain in the middle of the woods. This may not have been a good idea as far as snakes go. Is there anything I can do to repel snakes that will not harm the food I grow next spring ? I wonder if sevin dust or even one of those 'pest repellent' buzzer things would work. I have electricity at the garden.