Hydroponic St Johnswort

Any thoughts on growing St. John's Wort hydroponically?

We don't know anyone doing it. We are skeptical that it can be profitably done given the capital cost. But then there are people that advocate growing echinacea hydroponically. Apparently there is someone in Alberta who is doing that (but we don't have the name – we have only heard about it indirectly). Among the advantages cited for hydroponic echinacea production are clean, easy-to-harvest product and a faster growth cycle.
You will have to check the effect of hydroponic culture on hypericin content. There is no information on how that might be affected.