If you've attached the photos yet, I don't see any. More detail would be needed before a critter can be diagnosed! Is it dug holes? Are the plants actually being destroyed, eaten, etc.?

Shoot. I’ll try again.

There are several things that will do something like this. Seems like an armadillo scatters the dirt outward more, and digs deeper, than these seem to be, but don't rule it out. Could be a skunk, do you ever smell one when you get up in the morning? Maybe an opossum. Sometimes wild geese will, but they don't seem to be that active at night. They are most likely after ants or grubworms. Take your shovel and dig around in that area, I bet you'll come up with some nice fat grubworms. I dig those up whenever I plant anything that requires me to dig a hole. They are larval stage of June bugs and/or Japanese beetles. I put the ones I find in a clay flowerpot saucer and set them out where the birds can find them. The birds are needing protein right now to feed to their young.

I’m still perplexed by whatever is doing this. I’ve confirmed that it all happens at night, consistent with an armadillo. But it’s odd to me that 1) the digging occurs on both sides of my privacy fence, and 2) the digging occasionally occurs in flower pots and a raised bed herb garden. Doesn’t seem that a dillo would/could do that.

What about rats? Do they do this?

I put out a whole container of Critter Ridder. This is black pepper and capsaicin. It did not deter.

Grasping at straws, would an application of old fashioned urea deter, I wonder?

Penny for your thoughts.

Yes, could be rats. They will dig shallow nests to have their babies in. You might try leaving some D-Con and see if it's disturbed the next morning. They often will drag it into the hole if it's one of those little bags of granules. I wouldn't leave D-Con in the open, though, unless you like the idea of birds falling dead out of the sky. I don't see why you couldn't try urea, I'd try everything I could think of till I found something that worked.

We had an episode with a good-sized snapping turtle. He dug up my buried kitchen scrap compost and made a mess, dug into the yard under the fence and then under the shed. But we caught him (or her) going towards a neighbor's pond when the wild geese were walking their little goslings about, Hubs got the .22 and sent him to turtle heaven. Such big claws. Not safe to let those wander about now that so many of our neighbors have little grandchildren that visit often. We left him out there and something had a meal, Hubs thinks coyotes, because they left a thank-you pile of scat nearby.

We also looked out on the patio the other day to see a big black snake sunning himself. Turns out he snuggles down along the edge of the patio and has pushed the soil and mulch away to leave himself a sort of a trench. He is not venomnous so we decided to leave him be for the present time. He is a good mouse and rat-eater. We just have to be careful where we step. And not go out in the yard at night when it's not light enough to see.

Ah, life in the country....

Looks like dillo digs to me...dillos can dig under a fence.