I have been dying to try cultivation in semi-hydro for years, and a couple of months ago I finally went for it. I chose a few test subjects and so far the result has been overwhealmingly positive! Here is a status report:

Paph american hybrid Paph american hybrid Phalaenopsis marbella Maxillaria variabilis (red)  42_Maxillaria_variabilis_(red)_2009-01-13

  1. Paphiopedilum american hybrid in semi hydro 3 weeks… the roots have grown several cm – down into the water! Looks like it was thirsty…
  2. Same Paphiopedilum american hybrid after 6 weeks – a bud!!
  3. Phalaenopsis marbella after 6 weeks – a flower stalk is forming.
  4. Maxillaria variabilis (red) after 7 weeks – two new bulbs are forming. See this plant when first placed in s/h here.
  5. Maxillaria variabilis (red) same plant after 8 weeks – a bud!

I have a few concerns about the leca accumulating salts over time and eventuially harming the plants since I do not use R/O water. I am using the condensed water from the dryer with 10% tap water so the pH does not dip too low (thanks for that tip Berrak), but I am still keeping a close eye on my test subjects to see when I have to replace the medium.