Preventing a Terrier Digging Out

I've had a new solid board fence put in.  It's great for privacy, but the weak link in all fencing, as far as the dogs are concerned, is always at the bottom.  The top line of a fence should run straight on flat ground, but the earth always goes up and down a bit, and a dog can always dig out.  How to prevent that?

The traditional method is to put galvanized wire fencing along the ground or inside a filled in trench. The fencing should extend at least two feet back or down in order to prevent the dog from digging underneath.

I find stapling the barrier material to a bit of wooden furring strip, and then screwing that to the wooden fence makes for a strong and reasonably attractive edge without offering up a spot for the dogs to grab.

Instead of galvanized chicken wire or fox wire, which will eventually rust due to contact with the ground,  I am putting in welded plastic Yardgard hardware cloth which I picked up at Southern States and which was pretty low cost. With luck, this stuff should last forevever (or at least as long as I will).

I don't think this plastic fencing is tough enough to keep out a very big dog, but it's bonded at 1/2 inch centers, and it should be difficult for a small terrier to dig through it when it is rolled out flat, lawn-stapled to the ground, and covered with dirt, mulch, gravel and plants. For now I am putting it in a small section of the yard and leaving it exposed to see how the dogs react to it. So far, they are not digging where it is matted!