Digging
Digging is a normal behavior for dogs. In the wild, dogs dig to make a bed, find prey, or hide a cache of food. Domesticated dogs dig primarily for entertainment, although an ancestral impulse may be at work as well. The point is that your Lab isn't digging to annoy you; he's just occupying himself while you're gone. Fortunately, there are ways you can redirect or prevent digging.
Digging Deterrents
One way to prevent digging is to provide your Lab with more exercise and playtime. You want to make him too tired to dig. When that's not possible, make sure he has plenty of interesting toys that are more fun than digging. Look for a Giggle Ball or Buster Cube. Giggle Balls make — naturally — a giggling sound when they're pushed, and Buster Cubes can be filled with treats, which the dog can only access by manipulating the cube. Stuff a large Kong with treats, and leave out a soccer ball or a supply of tennis balls.
Redirecting digging is another option. Give your Lab his own sandbox or dirt pile where he can dig to his heart's content. Define it with a border of railroad ties and stud it with toys or rawhides that he can dig up and enjoy. Whenever you see your Lab digging in a forbidden area, distract him by saying “Aaaght” or “Leave it,” and then show him his digging spot. When he digs there, give lots of praise: “Good dig!” Reward him every time you see him digging in the right spot.
Never use cruel and ineffective methods to prevent digging, such as filling a hole with water and forcing the dog's head into it. Instead, try filling holes with rocks, gravel, or pine cones, so that it's no longer comfortable for the dog to dig there.
If your Lab likes to dig in your garden, put a picket fence or chicken wire around it to deny him access. You may also want to consider surrounding the garden (or other favored digging spot) with a new type of electronic fence. The dog must wear a special collar that activates whenever he crosses the boundary, giving off a burst of citronella spray. Dogs don't like the smell of citronella, so this type of fence offers a self-correcting method of preventing digging in specific areas.
Try a Change of Scenery
Is your dog digging to find a cool place to lie when it's hot outside? Consider moving his doghouse to a more shaded area. In warm weather, provide a plastic wading pool for your Lab to splash in. If all else fails and your yard is starting to look like a minefield, keep your Lab indoors when you can't be there to supervise. Another option is to build a dog run in the yard where he can be confined when you're not home. Give the run a concrete base to prevent him from digging beneath the fencing.

