Rockwool is produced from basalt rock, which is melted and then spun into thin fibres. These are mixed with a binding agent and compressed into slabs that are cut into the smaller cubes used for propagation. Fibres in Grodan have been spun in only one direction but Cultilene's Cultiwool propagation cubes have fibres that have been spun in two directions. This gives the cubes great flexibility and great strength when they're wet so they won't go all soggy on you. Seasoned hydroponics experts swear by Cultilene's Cultiwool propagation cubes because of the support and good aeration properties they provide for strong root growth. A healthy root system means a healthy plant and Rockwool propagation cubes can be used with even the most fragile cultures. Two sizes are available: Large - measures 36mm X 36mm X 40mm Small - measures 25mm X 25mm X 40mm Highly recommended.
