A friend in our ward did the upside-down tomatoes in 5 gal buckets. They line the outside of her raised garden beds. Since she tore up part of the yard to put in the garden, she attached soaker hose to the sprinkler system and extended it to all the hanging tomatoes so everything gets watered even if no one is home. This year she planted herbs in the top of the bucket.

This is what it looked like last year: