Well, I *am* Ray or Al, which puts me in good but relatively thin company
when I consider the other orchid know-it-all type people milling about in
this newsgroup.

In my greenhouse relative humidity generally goes down during the day and up
at night, and this makes sense to me because air cools at night and can hold
less water vapor. The warmer the air, the more water it can contain, and
the cooler the air, the less it can contain. Relative Humidity expresses
how much moisture is in the air as a percentage of the total moisture the
air can contain at the current temperature. For a given amount of water in
the air, the relative humidity will change inversely with temperatu as
the temperature drops, the air becomes relatively more saturated, and the
relative humidity goes up.

If you grow in a home rather than greenhouse you will not see rh much above
about 40 to 50% very often. And only this high if you work at it. Grouping
lots of plants together is the best way to increase it because plant
transpiration puts water into the air in large amounts. (I would bet they
put out more water at night than during the day, but I don't know for sure)
Ferns are humidity factories and very helpful plants for low humidity areas.
Most orchids will get somewhat used to these lower humidity levels in a
home. Putting mist in the air around plants may help a bit to keep humidity
up and will work best if the area into which it is pumped is separated and
isolated from the larger volume of dryer air circulating about your house.
Putting mist on the leaves is a dangerous way to raise humidity and probably
not very effective anyway. A thin layer of moisture on leaf surfaces is
exactly what fungus/bacterial spores want. Don't give it to them. A lot of
customers seem to think watering the plant more often will help compensate
for lower humidity, perhaps by making more moisture available for
evaporation. This will lead to root rot problems. Only water when the
plants need it not when the air needs it.

Your source below says humidity should be lower at night than during the
day. I think this might be a general recommendation meant to help control
fungus and bacterial diseases, although humidity is probably the least
controllable environmental factor you have to deal with. Perhaps the author
is trying to say something like, 'if you have a humidifier on during the day
turn it off in late afternoon so conditions ripe for fungus/bacterial
problems can not develop when the sun goes down and/or the lights go off and
cause the air to cool and moisture to settle out of it and onto plant
parts."


"Kenni Judd" wrote in message
...
I'm not Al or Ray, but ... ours live with what Mother Nature gives them.
--
Kenni Judd
Juno Beach Orchids
http://www.jborchids.com

"PhalGuy" wrote in message
s.com...
Hello AL ! or Ray !

I have read in many books and on the monreal botanical garden that the
relative humidity for orchids like Phal, Paph, Onc should be at around
70%
during the day and 40 % at night!

Is this true? Do you do this or do you maintain the same percentage of
RH
all the time?

Thanks

Claude

PS: AL, I`m very jalous of your greenhouses ! Can I go work for you!
:-)


--