All planters from Krebb's Concrete are made out of hypertufa.  Hypertufa is a man-made approximation of natural tufa,
a porous limestone used extensively by medieval farmers in Europe who carved it into feeding and watering
troughs for their livestock.  Victorian era gardeners realized that these "tufa troughs" were ideal for container gardening
because of  their unique ability to create micro-environments suitable for  bonsai and the cultivation of alpine miniatures.   
Contemporary gardeners have turned to hypertufa as an affordable alternative to the rare and expensive antique troughs of old.
They have also discovered that hypertufa is a material that encourages the growth of moss and lichens on its surface, making
these rough-hewn planters appear ancient once established in the garden.  Each planter at Krebb's Concrete is handmade
and decorated making it a one of a kind garden conversational piece.