Water Culture or Vase Culture

[Arizona Jeanie]

Hello all,
When I first started learning about proper care of Phalaenopsis, I read a great deal about how to prevent root rot. That seems to be a common cause of their demise, so I carefully potted in a coarse bark mix, let them get quite dry before watering, and repotted into fresh mix when the old stuff started breaking down. My plants have done well, roots are healthy and without rot, and they've bloomed every year since.
So, after all of the above, I was astounded to read about full water culture or vase culture--whatever you want to call it. I had to try it right away, stuck a NOID phal in a quart mason jar, and waited for it to die from those roots being not only wet, but in water much of the time. That was a year and a half ago, and the plant is going strong. I had to move it to a bigger vase to hold all the roots, and it's just starting to spike again. Three new leaves this summer. It looks just as happy and healthy as the plants in bark.
My question for you-all is this: why are roots in media so prone to rotting if they're kept too wet, yet the plants thrive when the roots are constantly wet in a vase?

[Subrosa]

The roots are wet in water culture, but they are also well aerated. When media gets sopping wet the roots can get no exposure to air, which causes the rot. The roots of most of my Cattleya in semi-hydro are constantly wet and the plants grow well.

[Arizona Jeanie]

How much air circulation is there inside a vase that is full of roots and has 2/3 of its open top plugged up with the top of the plant? Must be enough, I guess.

[Subrosa]

Originally Posted by Arizona Jeanie

How much air circulation is there inside a vase that is full of roots and has 2/3 of its open top plugged up with the top of the plant? Must be enough, I guess.

More than in a pot full of soggy bark or sphagnum.

[Arizona Jeanie]

I've gone from filling and emptying the vase daily to leaving a small amount of water in the bottom, about one quarter of the way up. That water's full of roots--how do they not rot?
Thanks for your answers, by the way. I never thought that vase culture would succeed, I'm trying to understand it.

[Fairorchids]

The roots adapt to the conditions they encounter.

Roots used to hanging over the edge of the pot won't like sitting in water, but new roots growing into the water are fine.

[Arizona Jeanie]

Well, the spike that started a while back is looking a little unusual. The first three nodes along the spike seem to be growing spike branches instead of buds! I'm taking that as a good thing, can't wait to see how it blooms. Last year's spike is still green also, I wonder if that will flower too?

[No-Pro-mwa]

Sounds like it is doing well.

[orchidsamore]

The confusion comes from thinking that too much water causes rot. It does not. Rot (pythium fungus) grows when the alkalinity of the medium gets too high When it gets past about 8 nothing wants to grow in it.

This never happens with water culture, nor will it happen if you change the medium often. I grow many orchids in Sphagnum wet almost year round. With constant replacing the moss and heavy fertilization I get accelerated growth requiring yearly repotting.

[Dollythehun]

Good info, Jerry. Thank you!