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