Plants may be grown hydroponically in a variety of inert media (something not containing nutrient) such as clay pebbles, rockwool, coco fibre etc and provided with nutrients in a nutrient solution or feed, in fact the plants can be grown in the nutrient solution alone as long as it contains enough oxygen.
Following is a brief introduction to commonly used hydroponic growing media.
Clay Pebbles: These are baked clay pellets that may be used as a growing substrate, they offer an ideal basis for hydroponic growers that like to control the application of nutrients to the root zone as well as the humidity. Clay pebbles are highly porous and have a high air content which stimulate the formation of strong roots, they are also pH neutral and pest free. Canna and Bcuzz are both high quality clays.
Rockwool: Rockwool is a mineral wool that is manufactured from volcanic rock. The rock is heated and spun to make rock fibres which are then bonded to make a variety of different cultivation products such as propagation cubes for seedlings and cuttings, transplanting blocks, slabs and loose grow cubes. Rockwool in nutritionally inert and allows the grower to precisely control the nutrients available to the plant as well as the pH of the root zone.
Coco Coir: Coco coir is made from the left over husk from coconut production. It is a natural media that is environmentally friendly, easy to use and gives great results. When selecting a coir medium opt for one that has been buffered to ensure its suitability for growing such as CANNA COCO. In addition some quality coir such as CANNA COCO contains a special fungus called Trichoderma which protects plants against soil borne diseases. Used coco coir makes an excellent soil improver for your garden after use. Coir is available in various forms such as pre-formed propagation plugs, transplanting blocks, slabs and loose media. Well recommended to the more environmentally aware grower.