i grow a bunch of peppers outside every year, in all kinds of containers - regular plastic buckets, grow bags, whatever i have around. i do a few of these, too - something i picked up over on thehotpepper.com years ago. peppers love it. i am waiting a couple auto seeds to pop, and will give them a try in these things the next couple months. they kill it with pepper plants, so i suspect it will do fine with canna. just thought there might be somebody out there interested in this!