Soil Moist has been developed to reduce the amount of water needed to maintain vigorous plants and other green goods. When mixed in the soil, the crystals will soften and swell as water is added and absorbed. When the potting system dries, the polymer will release its water to the plant. Soil Moist acts as a water reservoir--even during periods of drought the stored water is released to the plant. The expansion and retraction of the polymer during the watering cycle helps soil aeration, which is important to all plants.