I have had a number of questions about semi-hydro lately. So I thought I would say a few words about it. First here is the list of Hoyas that I have personally grown well in S-H and flowered: megalantha, praetorii, lasiantha,davidcummingi, lacunosa, dolichosparte, samoensis, memoria, and linearis.
I’m sure there are many more that would do well, but I have not personally tried them. Not all Hoyas will do well grown that way. I have tried S-H twice with magnifica and it has not performed well at all. I don’t really think it is practical long-term for the larger Hoyas like imperialis or macgillirayi.
I have to say that almost 95 % of my Hoyas are grown the old fashioned way in a chucky airy mix of orchid bark, large perlite, a little peat-based potting mix, and what ever else you want to throw in to loosen the mix – tree fern fiber, leca, etc. The longest that I have been successful growing a plant in semi-hydro is two years. The longest that I have grown a Hoya in my conventional mix is eight years. Transplanting a plant in conventional mix and trellising or using a basket is relatively easy, doing the same for a plant growing in S-H is problematic.
Plants in semi-hydro do best when grown in a high humidty environment like the tropics, greenhouses, or grow –tents and terrariums. Try using S-H in the regular centrally heated house in the winter time. You can’t water it enough to maintain a hydrated medium.
Semi-hydro is great fun to play around with, and will do wonders for certain plants; I will continue to experiment with it, but will continue to grow the majority of my plants conventionally.