Answer: It is certainly possible to grow vegetables in containers. Leaf lettuce and tomatoes are in fact good candidates, although the largest of the tomato plants can require a truly huge pot such as a whiskey barrel to do well. For many tips on gardening in containers including best soil mixes, ongoing care, and even vegetable varieties to try, you might enjoy "Container Gardening for Dummies" by Bill Marken ISBN 0-7645-5057.
It sounds like you have decided to use pots, but here is a suggestion about the dog, too. You might be able to thwart the digging by fencing the vegetable patch normally and then adding about a two foot wide band of wire mesh buried horizontally along the outside perimeter of the fence. This usually works on determined garden pests, so it might work for your dog.
Good luck with your project!
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