profpam wrote:

Claude,

40 watts seems a little bit low for even the growing of a phal. I have
seen phals grown in the same light as cattleyas; however, I have been
told the key to growing phals is temperature and air movement. So,
perhaps, with only 40 watts you aren't even growing phals. Curiosity
has got me now. What other greenhouse bottom dwellers will grow at
minimum light -- 40 watts?



More a question of duration than intensity. I routinely grow paphs
and catasetum in some pretty dark corners. Most seedling orchids (of
the types I grow) fine in a dim corner, as long as they stay warm (a bit
of a challenge). My lights are on for 16-18 hours per day though. For
what it is worth, if you (the original questor) haven't bought a fixture
already, consider a four tube fixture. You can get them for ceiling
light applications ( think they are called 'troffers' for some obscure
reason). That is what I used for a long time (still have a couple, but
haven't needed to put them up yet). I've also had good luck with
putting two shop-light fixtures side by side. My rule was always to try
and achieve 1 tube for every 1' of bench width. Seemed to work.

Mixing cool and warm bulbs is nice for your viewing of the plants,
but I've never been able to convince myself that it matters to the
plants. That is after 10+ years of growing under cool white or the
cheapest I could find (under a buck each), with varying amounts (down to
zero) of external daylight. Your mileage may vary.

I wouldn't worry about how close you put them to the plants. The
closer the better. But, and it is a big but (...fight it.... ok), your
spikes will grow up into the tubes if you aren't careful. Best to
watch, and move any spiking plants to a windowsill or some other bright
location where they can develop fully.

Rob
--

Rob's Rules: http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a. See rule 1
3) When one has insufficient credit to purchase
more orchids, obtain more credit