OK, Peter. You're going to have to help me with this one:

You stated "Humid air is lighter than dry air". How can that be? Humid air
is dry air containing water vapor, so how can (stating it mathematically)
X + Y X ?

In reality, the heavier, humid air will stay settled around the plants until
diffusion or forced dispersion moves it away.

You're right: humidity trays may not help much, or at all, but they do
protect the furniture!

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Books, Artwork, and Lots of Free Info!
..
"Peter Aitken" wrote in message
news
"Ray" wrote in message
...
I cannot argue with your evidence, but I stand by my general comment.
There
are too many factors involved - air flow from fans, heaters, etc., how
well
sealed the room is, and those inconsequential laws of nature.

Nature always wants an equilibrium, i.e., no gradients. A single source
of
evaporation will raise the humidity in the immediate area, but those
airborne water molecules will quickly disperse into the entire room, and
if
that room is not sealed off from the rest of the house, into that full
volume as well - and beyond. The simple fact that household humidity is
low
in the winter proves that the moisture emanating from showers, sinks,
dishwashers, washing machines, our own perspiration and exhaling, etc.,
is
diffusing out into the dry environment outdoors.

If the %RH near your plants is 10%-15% higher than the surrounding room,
I'd
speculate that you don't have sufficient air movement.

You might find this of interest:

http://forum.theorchidsource.com/cgi...=000089#000005


You may be right - but I am not looking to establish equilibrium. Humid
air
is lighter than dry air, so there will be continuous evaporation, rising
of
the humid air from the tray past the plants and into the room. I am aware
that some air movement is good. But again, I am trying to create an "OK"
environment for orchids in a room that is regularly used, and I know that
I
will never be able to create an ideal environment or even close to it as I
could in a dedicated orchid room. I have considered partially enclosing
the
shelves with clear plastic. In any case, the trays cannot hurt the
humidity
situation and will serve to catch overflow from watering if nothing else!


--
Peter Aitken

Remove the crap from my email address before using.