ViaStone, an incredibly resourceful growing material, is derived from clay. Clay itself is renewable and plentiful making ViaStone a premium growing medium due to its ecologically sustainable quality. Use ViaStone virtually anywhere: the greenhouse, in propagation systems, for outdoor gardening, around shrubs and trees, as compost aeration, or as a hydroponic growing medium. When estimating necessary amount of ViaStone for your particular application understand that the 50 l and 10 l quantity is based on the standard Horticultural trade gallon = 0.71 U.S. liquid gallons.