What a beautiful garden you have. Ground squirrels are the critters that have done the most damage in my garden. They are similar to gophers in that they tunnel under everything and eat it up (except for potatoes, for some reason.) I have tried noise makers, putting water in their holes, and, as suggested by a farmer from California, flares. The flares, when lit and placed in a tunnel opening, and when all of the exits you can find have been filled in, emit cyanide gas that puts the critters to sleep, FOREVER!. This was a last
straw effort as I did not really want to kill anything. Problem is that there are more of them than I could ever reach this way. It helped for about a week,
Most of our gardens are raised, about waist high, 4 X 4 wooden boxes with 12 inch sides set up on stacks of
pallets. We had some luck with putting 12 inches of metal sheeting around the top edges. yhis kept most of them out but our game camera caught one bold ground squirrel sitting up in a box one night. I also found snowshoe rabbit tracks there. The only thing that actually works for us is, wait for it, bathtubs set on cement blocks, 2 high at each corner. No critter has yet been able to climb them. Actually, they have left my tomatoes alone as well. I plant tomatoes in stacks of tires, again about waist high. I fill them with dirt and anything that might be compostable, including
chicken straw, kitchen scraps, etc.
Given our 90 day growing season I cannot afford to start over, and over, and over.
Deer are also an issue but adequate fencing keeps them out, usually. Stock water tanks would probably work as well as bathtubs but they cost money and old bathtubs are often free Because we garden on the roof of our earth sheltered home everything in the garden has to be hauled uphill. For this reason fiberglass bathtubs are better for us than
cast iron. I wish that I could plant things in the ground, and certainly my garden of tubs is not beautiful, but gradually we are gaining some food security.
Best wishes to you.