If you are not opposed to using Milorganite, it keeps the squirrels out. I even feed my containers with alfalfa pellets on top and squirrels or any other rodent have never bothered them. Do everything you need to the containers or pots, water them, then I very liberally put Milorganite over the top. Water avs normal and in 3 or 4 weeks repeat...but after years of doing this, they leave my pots alone and I only do it 3 or 4 times a year. I have three pecan trees in my yard.
Milorganite is relatively inexpensive, but I do not consider it a complete fertilizer.
May you be blessed with a wonderful growing season.