advice needed

Hi there, I'd like some advice and help with a problem I'm having. I have 7 plants in 5 gallon smart pots outside and something keeps digging into my soil. At first I though it was squirrels and chipmunks so I put some rocks around the base of the ladies to make the soil unattractive to dig in. But whatever is digging in the dirt just dug through them so I'm thinking either raccoon, possum, or skunk. My question is what can I do to deter them. A fence is not a option. I have recently started pissing around the area in hopes of deterrring them and also spread some used cat litter around the area. A friend of mine suggested coyote urine as well. Any other advice would be greatly appreciated, thank you in advance.

Get some 2" chicken wire. Lay it horizontally around you grow area, suspended tightly about 6" above the ground. 4 feet wide is best. Those animals can't easily jump over it. All those critters taste good to coyotes and other carnivores. They won't risk trying to cross the wire. I use something similar to keep my cats from digging up vegetable seeds, looking for some place to shit. I picked this idea up from "Organic Gardening" about 30 years ago.

piss, blood, human hair evem heard of some cases of dog hair as well
As far as the digging goes I would get creative and think of some sort of barrier to protect it. if you cant use a fence try chicken wire or a wall of thick branches/sticks outlining your soil