The duration of the intensity does make a difference, else commercial
growers (like those in Taiwan, for example) could not 'force' their crop to
maturity in a short span of time. Herb Hager wrote a great article on
increasing light in order to bring his cattleya crosses to bloom in 2 1/2
years out of flask by supplying high light, high heat and supporting the
plant with high humidity and the proper fertilization regimen. If you read
Dr Yin-Tung Wang's research carefully you'll discover these same methods
were used to develop the phalaenopsis market. But you can't just do this
piecemeal, you have to support the plant wiht the concomittant increases in
water, humidity, fertilizer etc, that requires
knowledge/expertise/consistency on the part of someone growing these
orchids. A friend of mine (very successful in his own right) maintains that
a plant is merely a chemical equation, if you supply high light and neglect
the other parts of the equation (leaving them the same) your plant will
suffer and die. If you increase light and increase supply in all other
factors in the proper amount, the plants will flourish. As I say, its been
what has driven the pot plant industry world-wide. So 10,000 nurserymen
can't be wrong. It only remains for *you* to be able to control all
factors. Something a hobbyist is usually unable to do in a consistent
basis. One misstep and you've screwed the pooch. Also, I thik once you sit
down and start writing out what consitutes 'all' in the above sentence you
can readily see that there are factors, physical/ limiting/ specific, that
are practically unknowable to someone who also has a life. Its easier to
grow them under natural conditions. Letting God do the hard thinking.

K Barrett


"Larry" wrote in message
.. .
This brings up a question I've been wondering...

The intensity certainly plays a role, but what about the duration of the
intensity? In other words, is 16 hours per day at 1500 fc the same to a
plant as 12 hrs per day at 2000 fc (16 x 1500 = 12 x 2000)?

I know many plants including orchids want a certain amount of time in
light
and time without light, but I am not sure if the above example would make
a
difference.

Larry


wrote in message
rg...
On Fri, 01 Apr 2005 05:00:02 GMT in
Don Quixote
wrote:
According to the Ultimate Orchid (by AOS), "In general, most genera
will
grow well at light levels between 2,400 and 3,000 foot-candles."
Although most people say phal does better at 900 to 1200 foot-candles,
I
wonder if it will do well at 2,400 to 3,000 foot-candles?

Remember that a light that produces 3000 foot-candles at
distance x will provide approximately 900 foot-candles at approximately
1.8 times distance x.
The 2400 fc light will produce approximately 1200 fc at 1.4 times
distance
x.

If the Phals think it's too bright, you can just move the light
further away.

--
Chris Dukes
Suspicion breeds confidence -- Brazil