Eating dirt

Question
My 12 week year old puppy eats dirt,  I wouldn't mind except he has gone to the vet twice because he gets sick and won't and once worms.  I don't think it is boredom because he is in the apartment and does it on his walks where is he excited to be outside.  I don't think it is dietary, since we feed him good pet food and his blood work returns up without issues.  He does seem to go for the same places each time, he must smell something in the dirt.  

The only answer we have found so far is a muzzle and hope he grows out of it.  Which I don't like because it bothers him and gives others they wrong impression of him, making it hard to keep him socialized.  Also I want to stop it not just hope he grows out of it.

Thanks,

Answer
Hello, Michael!

First, I'm sorry you had to wait so long for this answer..

I couldn't understand if you said 12 week or 12 year? Which could be pretty significant information.
If your dog is 12 weeks, he could still be in the nosy, messy, playful stage, in which it's not uncommon to find him tearing up the yard, yipping at the curtains, or chewing up a boot.

If he's twelve years, however, it could be a much more serious problem. As a dog ages, his digestive system weakens, and you might consider mentioning this to your vet as it could be his way of announcing a much larger problem.

Also.. Maybe you're not giving a possible dietary deficiency enough consideration..
Most pet foods that are generally considered "good" are low quality and contain ingredients that, believe it or not, your dog (among close to 80% of all dogs) may be allergic to.
His food may be lacking in vital nutrients, so he's eating dirt to make up for it. Mention this concern to your vet, and he may suggest some "doggy vitamins" to make up for this deficiency.
Also, How often do you feed him? A good idea is to feed a puppy three times a day, and a dog twice a day, morning and evening. Just plain hunger could be the reason, if maybe he isn't eating his fill.

It's also possible that he just enjoys the "taste"! Not something we could understand, since dogs senses are so much more powerful thn ours.

If you've discussed it with your vet, and it's not a diet problem, try keeping him on a shorter leash so he has to do a "heel", which makes it impossible to stray off and snack.

Hope all goes well! If you have any other questions, please feel free to write a follow-up :)