I'm going to have to respond in generalities, as it's been years since I
grew much under lights, but light intensity is an important factor in
blooming, so, short of burning, more is better.

A single 20W aquarium tube does very little, as its output is probably only
around 1000 lumens, barely sufficient to grow phals, let alone bloom them,
and well below the needed intensity for most of the other plants you
mentioned. The larger the bulb output, and the more you can provide, the
better.

A lot of folks recommend grow-light bulbs, but many find that 50/50 (in
terms of wattage) cool white/warm white is good, while I prefer the
sunlight-types - those with the "Chroma 50" phosphor (it's printed on the
bulb).

If you have a camera with build-in light meter, you can use it to measure
the light intensities. Follow the instructions at:

http://www.firstrays.com/measurelight.htm

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Books, Artwork, and Lots of Free Info!
..
"auntymo" wrote in message
news:LUhed.8624$Pl.576@pd7tw1no...
it's time to make room for some more orchids at my house, and i have a
couple of questions about indoor lighting...

we're going to make a new plant stand, and i was just wondering what i
should get for lighting. what is a biaxial fluorescent light? should i
bother? i see they are used in wardian cases/orchidariums and aquariums.
are
they some sort of high intensity fluorescent? i'll be supplementing the
natural light coming in the room (unfortunately i don't have a light
meter)
so i don't want anything too crazy, but i do want to make my medium light
orchids happy.

i grow them in a room with a large south facing window (there is a large
tree out front which shades half of the window in summer), and there are
plans for some small windows to be put in the east side at some point in
the
future. anyways, my little friends live on the west wall under a
fluorescent
light (my husband says it's a 20 watt aquarium grow light? i didn't get to
see the box). they are all doing very well, but since i'm a bit new to
this
i am still waiting to see if i will have luck blooming anything. all new
growths seem to be getting enough light, they are light green, upright and
firm, and the phals have a slight red blush along the edges of the leaves.
i
have various types, phals, an oncidium, a miltonia (or miltoniopsis...is
there a way to physically tell the difference between them? i think their
temp requirements are different?, but i digress...), a miltassia, a
neofinetia, a paph, a zygo, a wilsonara, dendrobium, and soon a
sarcochilus,
and miltassia (lol yes the bug bit me hard, i'm also experimenting to see
what likes me and what doesn't).

sorry my post was a bit longer than i though it would be.

--mo--