I have gopher issues. Like, bugs bunny cartoon issues, like watching things being pulled under while you are standing there issues... Lay some hardware cloth down under those tires first. You won't know to thank me, because you won't have hollow potatoes.
I plant tomatoes in tires have for 3 years. I don't have a way to plow so I use tires and purchase my soil by the bag. this year I am going to plan green onion sets and lettuce in tires. I was able to shovel enough dirt an poo out of one of my chicken pens and i belive onions will do well but I will not use this for my tomatoes as I belive that tomatoes wont do well in the poo dirt. anyway tires are great you can water and the inside of the tire is like a resorve for water.