/diy/ - Do It Yourself

If you want to train the animal aversion training works, but don't hit the thing. Just get an air horn or make a "penny can" which is a couple of pennies in a metal can (empty soup can works). Both are incredibly loud and won't hurt the dog at all. (just don't airhorn him within 1' of his ears) The best way to do this is to sneak up on him and airhorn/pennycan him while he's in the act. Do your best beforehand to let him know that the area is off limits; once you do catch him digging, after you scare him with the airhorn/pennycan, act severely disappointed in him. It will help if your wife does the same thing. I'm talking "father just found out his son got his cousin pregnant" disappointed. Act like what he's done is the worst thing in the world. This might seem silly, but dogs actually can pick up on human expression very well. (not as well as people though, which is why you are overacting)

Alternately you could properly train the animal, but if it isn't yours that may be hard to do, unless your wife is in agreement. A properly trained dog can be told a "leave it" command and they will leave alone whatever you told them to indefinitely. Although keep in mind if he's a breed that is bred to dig (ie terrier or other "earthdog" breed) it will be difficult to get him to stop digging entirely, especially if you do have something (groundhog, mole, etc) under your yard.

As for the barrier, if you're willing to spend a little bit they sell rolls of galvanized metal flashing pretty cheap at hardware stores. For ~$20 you could get a 8" x 50' roll. It would be a lot easier than making it out of milk jugs, since it would be a continuous piece and would lend itself well to being put in a circle. Many people use them as weedwhacker/yard trimmer barriers around their trees.