Soil Moist granules are the eco-safe, water-storing polymer crystals. Simply mix some into your soil at planting to reduce watering by 50%. The crystals swell up with water then act as a slow-release watering system. Perfect for hanging baskets, hot dry locations, or water-loving veggies. The crystals last 3-5 years in the soil. Approved for organic gardening. Sold in 3 oz. bags.