Prilled granulated stone wool is a soilless media that can be used alone or as an amendment to organic based mixes. Grodan Gro-Wool is designed to expand with water holding capacity that is able to hold 25-50% of its volume in water while aerating roots, maximizing growth. The water repellent granulates are superior substitutes for aerators such as perlite or Styrofoam. Grodan Gro-Wool is the only mix that the professional grower will need during the entire life cycle of the plant, leaving time for fertilizing, spraying and plant maintenance for efficient gardening. Grodan's Grow-Cubes™ are for use as a loose growing media. Grow-Cubes drain easily, naturally retaining a 50% water to 50% air ratio. Allows for a lighter weight media which can be mixed with other growing medias such as coconut fiber.