Crystal soil (a.k.a. soil moist) is water absorbent polymer beads, which can absorb and hold up to 80-150 times of its volume of water for a long period of time. As a reservoir, crystal soil stores water and releases the water whenever the plant needs it.
Crystal soil can be used for potted plants, both indoor and outdoor. It is non-toxic, odor free, and environmentally safe. It appears that while gardeners around the world know crystal soil and use it as a soil additive for potted plants, only those in Asian countries use crystal soil alone as a beautiful growing medium in clear containers.