Yes Rick I have Lance Birk's book and looking forward to getting Averyanov's.
I've also noticed that some roots can survive totally submerged in water as long as the bulk of them is above it. They must be supplying air to the bottom ones? I have a feeling that totally submerged is different to constantly wet. Possibly because the submerged roots are not subject to attack by aerobic pathogens?
And yeah I saw that bellatulum--amazing!
If you think about it, many of the orchids we grow are "constantly wet" in nature, depending upon the climate of their habitat.
Yes, moisture can play a role in the spreading and development of a variety of pathogens, but it doesn't mean that it's a "must".
In my S/H presentation, I have a slide of a reed-stem epidendrum growing and blooming with its root system entirely submerged, so the roots must be getting their oxygen out of the solution.
My stance is that the roots tailor themselves to whatever environment they are in as they grow, so they can function optimally. Constantly wet, or constantly submerged, once they are grown, they will support the plant just fine. It seems to me that wet/dry/wet/dry is probably more stressful.
Once you've decided which way you want to go, the trick is to understand how that interrelates with all of the other aspects of your growing environment so you can make appropriate adjustments. Simply changing the water delivery without considering other stuff is a good way to head to failure. For example, a lot of beginners get the mistaken idea that s/h culture is 'the best" for all plants under all conditions, so they plop their phalaenopsis into LECA and away they go. Come winter, when thermostats are pushed low to save money, and the RH% plummets anyway, suddenly the evaporative cooling from the open, airy medium drives the root zone temperature to lows that the plant doesn't like, and they start losing roots.
I do want to reiterate/clarify an earlier comment about flushing: flushing "every time you water" is a good practice, but what I was trying to say is that doing so more often is better than less often.
No matter how you are growing the plant, flushing the pot more frequently will lead to better growth than doing so less frequently. When I used CHC or bark (straight Orchiata, these days), I tend to go with a coarser size than most folks, precisely because that prevents bridging water from totally filling the voids between particles and suffocating the roots. That allows me to water more frequently (as I don't have to wait for absorption and evaporation to open up the mix again), which flushes residues and sucks nice, fresh air into the root zone as it pours through.
