I'll be interested to find out the answer to this as well. I have so much I want to plant that I'm trying to figure out what I can plant on our deck now. So far I have moved all herbs to just grow in our bed by the deck (I tossed what I thought were dying ones in there last year and they tourned around and flourished when I stopped messing with them...go figure!). I'm also going to try potatoes in a trash can and strawberries from a bucket.

A friend of mine swears by the "crystals" for container gardening, but I know nothing about them...