A hydroponic growing medium should act as an anchor for the roots so as the plant does not fall over as it grows, provides good drainage of the nutrient solution, and allow the flow of oxygen to the plants roots. There are many different types of growing media, as anything that a plant can grow in is considered a growing medium. There are man made as well as organic (natural) growing media. Even air can be an effective growing environment for roots, such as in a aeroponic system.

Many people will ask which growing medium is the best. This is like asking, “What is the best color?” Or “What is the best kind of vehicle to own?” The answer depends on the job you need it to do. Different growing media work better for different growing systems and different plant types. There are many factors to consider, such as water and nutrient retention capabilities, what kind of growing system you will be using, and whether or not you wish to re-use the media for subsequent harvests.