Growing Medium
Although there is no soil in a hydroponic garden, the plants must still be anchored. There is a wide range of inert materials which can be used to support plant roots and we call them "growing mediums". Heydite, clay pellets, Perlite, vermiculite, and Rockwool are the most popular media. The hydroponic media that work best are pH neutral, provide ample support for plants, retain moisture, and allow space for good air exchange. The type of media you choose will depend on the size and type of plants you wish to grow, and the type of hydroponic system being used. For continuous drip systems, a course media Hydrocorn (clay pellets) is best. The 1/4 " to3/4 " pebbles provide enough free drainage and air space to take advantage of continuous feeding. These media also provide good anchorage for larger plants, and are easy to clean and re-use indefinitely.

Some hydroponic systems do not require any growing medium at all. Various methods are used to support the plants while the roots are directly fed nutrient solution. Some examples of these are, aeroponic, N.F.T., or "Nutrient Film Technique" and deep water culture.