Product description from the manufacturer This Product can be use alone of mixes with Orchid Bark Composts Seramis clay granules are made of small, light, porous granules with high water retention qualities. The fine pores absorb moisture, retain it and release it again when needed. So your plants take exactly what they need. Seramis clay granules are structurally stable and do not compact. So the roots are provided with the right amount of oxygen. This leads to particularly strong growth and leaves your plants looking healthy and beautiful - in a completely natural way.