aversion tactics like the bag fence and pie plates may work well. Couple things to think about: how long do you need it to work?

There is alot of research to suggest that scare tactics only work for a certain amount of time. Typically they figure out pretty soon that the scary noisy things aren't a threat. Also researchers have found that when food supplies are low, just about nothing will stop them from getting into your plot.

But try it and see how it works. Good luck!