Just read the artical about them.Its somewhat changed since I last read about it which was about 2 yr ago.Seems a little simpler but its basically what I said bar all big jargon!!Instaed of the soil breathing air through the roots the bunnles do it probably more efficent depending on the quality of draininage in your soil ie loose or compacted soil.The herb I tried in Holland wa said to be from an aquafarm but I,m not sure.