I apologize for this delayed reply to your gardening question. The spring rush has brought a deluge of questions and we are working hard to catch up!
I'm not sure there's much that you can do to prevent squirrels from digging other than placing some type of mesh wire over the area where they are digging. This is not practical throughout a large landscape area, that may be in a small flower bed where you wish to protect some special, valuable plants.
You might try contacting your County Extension Office to see if they have any suggestions for deterring squirrels, landscape.
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!
Q&A Library Searching Tips