If you let the medium dry out, then you are not growing in semi-hydroponics!
What you are doing is merely growing in LECA using "normal" culture.

If you try to do S/H but let it dry, then your plants won't develop the root
cell structure needed to survive, and they will rot. The idea is to get
them to grow roots accustomed to the constantly damp but airy conditions.

If your epi's developed the correct kind of roots but are now rotting, it is
likely due to insufficient warmth.

--

Ray Barkalow First Rays Orchids
http://www.firstrays.com
Secure Online Ordering & Lots of Free Info!


"Geir Harris Hedemark" wrote in message
...
I have a number of epidendrums keikis and a dendrobium in SH
culture. The Dend. is in a clay pot, the epis are in smallish plastic
pots.

The dend. seems to enjoy life. The epis have stopped growing. I think
it may be caused by them staying wet too long (well over one
week). The pots have holes 1cm/0.5in up the sides, I never leave any
standing water in them. Only one type of expanded clay pellets are
available locally. I need to exchange the pellets after about three
months because of algae buildup which clogs the holes in the pot. The
roots of the keikis that are in the bottom have started turning
brown. Wether this is rot or dust from the pellets, I don't know. The
pellets dry out about 4cm/1.5in down before I need to water again
because the leaves on top have gone limp. The roots go about 10cm/4in
down into the pot, but seem to want to spread out instead of going
down.

I see this as a problem - is it?

Are there any tricks that will allow the pellets to dry out faster?

Geir