Kevin,

What kind of damage are you doing to the house? Remember the house was not
built to stand the kind of humidity that you are providing for your plants.
I don't know if you own or rent but you may be asking for problems someday
with mold and other stuff growing in the walls if you keep the humidity too
high for a long period of time.

The dendrobiums need good strong lighting. It's really difficult growing
plants this size under florescent lights. The top of the plant gets good
light but the lower leaves are not happy. Under florescent lights you need
to be about 4 to 8 inches from the surface of the leaf. That's easy for
small plants (seedlings) and flat plants such as phals. Taller plants like
Dendrobium, Catts, Oncidium family, etc. get too tall to do well under
florescent tubes. You should consider Metal Halide which give you about 4
feet of good light (depending upon wattage).

Temperature will become an issue when you add more lights. Venting to the
outdoors can help some of this but on a hot summer day it's difficult
controlling the heat. Last summer I had to keep my phals under 1000W Metal
Halides in the garage. There were some days when the temp got over 100
degrees. I kept the air moving and the garage doors open when I was around.
I still have phals with blotches of different color on the leaves that I
believe was caused by over heating. Now that I have them in good temps the
new leaves are growing out normal and healthy and in another year or two the
damage will be replaced by healthy leaves. I don't know what is the magic
temperature where damage occurs but the plants will cook even under the
lights if the air temp gets too high.

Air movement is very important. The evaporation of the moisture lowers the
surface temp. That same evaporation can dry out plants too. I don't like
to have the fan blow on the plants for long periods of time. When I grew in
the house I had several of the fans that moved back and forth to keep the
air moving all over the room. Another thing is to keep the fans going 24
hours a day. The plants need the air moving across the leaves even when the
lights aren't on.

Good Growing,
Gene



"Kevin" wrote in message
m...
So my plants are in a spare bedroom- a bit of natural light (more in
the winter, less in the summer- decid tree outside window), and 4
florescent tubes over them- 2 cool white, 2 "daylight".

The question is about temps. I, of course, heat the room in the winter
here in Missouri. Nice temp difference between day and night, maybe 55
night and 73 day. But in the spring/summer/fall, I leave the windows
open and let it go. Of course, it's humid as all get out, and I keep a
fan circulating, but the temps hit the 90's during the day, and may
not even get down into the 70's at night.

I grow mostly Phals and Dends. I'm fairly new, but so far no problems
with either. The Phals rebloom, and I even have a spike under
florescents on a Dendrobium! I'm wondering about long term
consequences- slow growth, etc. I am getting new growth on the
Phals....

What do you all think? Will they all flourish given the proper
humidity and lots of air movement? What will suffer?

Thanks for your knowledge....
Kevin