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.
CEMENT PAVER PLANTER BOXES: All you need are a few - pavers, - landscape-block adhesive, and a little time. Wait 24 hours for everything to cure and you're ready to move your new planters into place and fill them with dirt and greenery.
How to Make Tree Stump Planters. (I like using tree stumps still affixed to the ground by roots after a tree is cut down, with the center scooped/carved out -- it looks a lot prettier and much more natural)