The function of the growing media is to:

- provide support for the plant;
- ensure that water and nutrients are available to the plant's roots by absorbing and retaining moisture;
- provide air circulation and drainage; and
- to provide the protection for the roots from temperature changes. 

The media should not contain any of its own nutrients nor affect the pH of the hydroponic solution applied. Different media are suitable for different types of systems as well as being appropriate for different plants.

For commercial growers, Growth Technology recommends bulk slab cocopeat.