Grodan Gro-Wool Medium Water Absorbent Granulate, 3.5 cu ftIf you're growing water hungry plants in containers then Gro Wool is a good idea. Gro Wool can support house plants while watering just once every 2 to 4 weeks. When growing in clay pellets mix in Gro Wool to make water and nutrient distribution more uniform and have a moisture buffer in case the pump fails. Gro Wool also promotes fine root growth which leads to larger more vigorous growth. TIP: If you are using a drain to waste system, then you do