I am interested in building a small - scale hydro system just to get more familiar with how it works. I plan to grow some basic easy-to-grow vegetables at first. So I have the container, an old fish tank pump, organic fertilizer and now I need the rocks for my setup. As the title suggests, what are these rocks called and where would they be available to buy most likely?
Here is an example of the rocks:
I think you are referring to a hydroponic clay aggregate known in Europe as Hydroton where it is manufactured in Sweden.
It may also be called Geolite, HydroKorrels, Hydroleca or "grow rocks". Other products such as growstones, which are made of glass, tout themselves as a superior products.
Commercial growers often use rockwool cubes or trays to start hydroponic plants.
Judging by the ads I see listing it for sale on Ebay, Amazon, Sears and numerous other sites there is no shortage of it. Just search for hydroponic clay aggregate.
