Make cement cloth planters. Approximately a water/cement ratio. Add drainage holes in the planter before it completely hardens to prevent cracking. You may also want to apply a couple coats of cement sealer after the planter is dry.
DIY PLANTERS :: Making Hypertufa Pots Tutorial :: Hypertufa is a stonelike material that mimics a type of rock. Make flower pots (or balls/pillars) in any shape & size w/ just THREE INGREDIENTS! She shows you her method.