Retain Water Retention Crystals For Hanging Baskets, Flower Pots & Planters, Garden & Yard. - Water Less Frequently - Healthier Plants Retain plant crystals are a safe and easy-to-use soil additive made out of water-absorbing ingredients (cross-linked polyacrylate, bentonite clay, lava rock, and silicates) that absorb up to 40x its own weight in water. 50 lbs of retain can hold up to 250 gallons of water. It increases the water-holding capacity of soil by up to 60%, helping to prevent waterloggi