Rockwool will allow the grower an easy set up, since it is pre-formed and modular. It holds a tremendous amount of water and offers a buffer against drying in the case of electrical outages or pump failures. As Rockwool is disposable, it lends itself to quick end of crop clean-up. Coconut Fiber is recently becoming more popular. It can also be added into soil mixtures to increase water retention.
Coconut fiber holds more oxygen than rockwool and is pH neutral.
It is fairly heavy, which provides secure support for the plants' root zone. This non-degradable, sterile growing medium holds moisture, has a neutral pH and will also wick nutrient solution to the plants' root system. Easy to use. Stick with dwarf or compact plant varieties when gardening indoors. They will perform better under lights and are lower maintenance.