I haven't had problems with squirrels eating the crops. They're too interested in the bird feeders. I've replaced the "squirrel proof" feeder three times.
My problem is chipmunks. I told the wife last night we need to get some snakes.
She was not amused.
I really like snakes.
I've never had to deal with chipmunks though. We have gophers like you wouldn't believe...I've actually pulled one out of the ground with a rake. I don't care for gophers...they make a mess. Big piles of dirt every where.
We also have moles, but they just kinda wrinkle up the sod a bit...
There are prairie dogs just a ways down the street...or used to be. I think the mean old dude gassed them.
I'd recommend just getting squirrel feeders :~)
We've never even tried to differentiate between squirrel food and bird food. We just put out a pile of seeds, and it's "first come, first served".
Do you hang your bird feeders from poles or tree branches? I hang mine from tree branches and use a "baffle", or plastic cover that you hang the bird feeder under. It swings freely above the feeder, and the squirrels just slide off if they attempt to get to the feeder, but they still have access to the seed that falls on the ground. You can get them anywhere they sell bird feeders.
If you have platform feeders, change to safflower seed; most squirrels don't eat that particular seed.
When I get home, I'll post some pics of snakes we saw on our vacation in PA. I've never seen so many snakes in the wild before, ever! We came across a den of eastern mtn rattlers. Fortunately it was cold and I had a good zoom lens... the pics came out great. The other occasion was a garden full of garter snakes.