don't forget to keep them well watered in addition to providing drainage! too often in small containers the downfall and death of the plants is lack of water, especially on hot days. one helpful tip is to use those silicone balls that retain water and slowly release it later. Good luck, let us all know how your garden does!
What a great idea! I have a sunny porch, so I've been growing my herbs in several strawberry pots. This is a much better use of vertical space. And they look very healthy. I hope you get great use out of them. You should publish your idea in Mother Earth News or Organic Gardening. They love ideas like this. :-D