Great recycling idea. Turn empty soda & water bottles into a self-watering vertical garden. I've gotta try this! It is also being promoted as a means of helping those in world dry climates to grow food. I love it. You will also. See the youtube video at
How to grow strawberries vertically with a PVC pipe support system. The instructions on this site are well-written. No heating/re-molding of the PVC pipe is required. PVC pipe can be painted. Lightly sand the pipe, paint with primer (Kiltz or Zinsser 1-2-3) to cover up any writing on the pipe and seal it, the spray with plastic spraypaint (Krylon Fusion).