Why use a Substrate in Hydroponic Systems?
The answer to this question depends a lot on the crop that is being grown. Substrates have been successfully employed in the cultivation of most vegetable vine crops grown in greenhouses such as tomatoes, cucumbers and peppers and some cut flowers such as roses and gerberas. Let us consider the advantages for using substrates with these crops. The primary reason for using rockwool, or any substrate, in a hydroponic growing system is to provide a buffering reservoir of nutrient solution in the root zone while maintaining an adequate volume of air (oxygen) in contact with the roots. In an NFT or other “pure” hydroponic system, the watering and feeding of the plants depends solely upon the flow of nutrient solution past the roots. If this is interrupted, for even a short time, the plant will die. On the contrary, if the root zone is flooded the roots will suffer for lack of oxygen. In a substrate system, the substrate maintains a reservoir of nutrient solution in the root zone along with
