We have 5 large garden boxes in our yard, but this year we didn’t use them all. The one left is high, and has cement blocks/ sidewalk in front, a cement block on one side, and rocks on the other. It’s bigger than it looks in the pics. If I took 1/2 the soil out would that work for my Russian Myrtel to be out in some days with a screen on top in case cats come by? I do have him roaming the yard but only if I’m out with him. Some guy in our area had his tortoise stolen so that’s a concern too. I’d read the Russians are avid diggers, so not sure if this is a great idea? I’m thinking if he tunneles out under the cement sidewalk , or that’s unlikely?