Joost,

If I'm not mistaken, the plants bloom in response to shortened day length,
not to light intensity directly - although I suppose there is a minimum
intensity the plants need to recognize it as "day".

Most of the time catts are forced early by covering them with black cloth to
shorten the daylength, so I'd guess that the flowering could be delayed by
keeping the day long via any sufficiently-intense light source. I suspect
that the closer the light intensity is to that of natural sunlight, the
better.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies. Books, Artwork, and lots of Free Info!


"Dogman" wrote in message
ups.com...
I hope some of the more experienced people here can help me with these
questions.

I have wide range of varieties in Cattleya, most of them start blooming
in winter as the days get shorter.
I strongly believe that for a lot of those varieties it should be
possible to control when they start to flower by controling the lenght
of the day and night.
So far i found that keeping the plants from flowering can be done with
tubelight or small bulbs.
It can be done by adding extra hours to the natural lenght of the day,
but also to give light in the middle of the night. My question is what
type and intensity of the light would be needed to do so?

regards, Joost