Cattleyas - Too much light at night?
 

I was watching an old video on the Rick L Orchids Youtube channel and he mentioned that in order to bloom, Cattleyas need complete darkness at night, even a porch light could affect this. When he mentioned that, I remembered a video in which Norman Fang also said something like "if you wake up a Cattleya, like turning the kitchen light at night, they won't bloom for you."

My understanding has always been that Cattleya blooming depends on daytime light as opposed to night light. I'm not sure I would trust the information provided on the aforementioned channels (although I quite enjoy Rick L's voice and his journey through illness and orchids), but I'm curious about whether I can find trustworthy information on this.

As many on this forum know, I live in the middle of a busy city and complete darkness is not achievable unless I lower my blinds, which I never do. However, it's hard for me to believe that some building's lights (or even kitchen lights) placed many feet away from the plants could activate any receptors.

Thoughts?

Changes in day length is the “trigger” in some, not all, cattleya species. Cut flower nurseries commonly spread black cloths over the benches to force plants for the holidays.

However, what the human eye perceives might not be of enough intensity to disrupt the short day.

As an aside, I take much of Mr. Fang’s advice with a large grain of salt. He’s very well educated and has a lot of good experience, yet he apparently doesn’t apply it to the plants he sells, based upon the comments I’ve read about rootlessness.

I have also read about light inhibiting blooming. Maybe it's an issue if you had a street light shining on a plant that is particularly sensitive. But where I live, there is so much light pollution that I can see only the brightest stars even on the clearest night, and my Catts bloom. If you have one that is particularly not blooming on a mature plant over several years and you can't identify a cause, maybe try to move it to a darker area. But I think the jury is out on this one. Like many other factors, it may be a matter of degree. I doubt very much that the "background city lights" that you see out of your window would be enough to cause a problem.

okay- strictly anecdotal, I grow my catt and related orchids in one general area and there are about 50 and i routinely leave the flood light on that is basically right over them.

While i do not track blooms and schedule i can say that all of these have bloomed in the last year. maybe not as well as possible but the presence of light is not a total killer

i suggest that Roberta is right (duh) see if one or two refuse to bloom over time and then move those

The only Cattleya species I'm aware of that requires absolute darkness at night is walkeriana. That trait seems pretty recessive and many of the "fake" walkeriana out there that look like the species but have loddigesii in the background seem to bloom in the presence of night light.

My experience with Cattleyas over the years has not led to any evidence of night light causing anything except pure walkeriana to withhold blooms, nor have I heard any evidence for such things from other growers until this thread. Both of the growers you mentioned certainly have good qualities in their videos, but both are wrong in this case.

I think there is some conflation of photoperiod (length of daylight), night light, and daytime light intensity. I adjust photoperiod from 11 hours during the winter to 14 hours in mid summer. I give them total darkness during the night and high light during the day. I think all these are key to maximizing blooming.

i am occasionally jealous of you growers who have absolute control of all aspects....pretty cool

Until the power goes out in winter!

As in...say good bye to ALL my phalanopsis. Living in the country has down sides. :(( :(

no!!!!!!