Light Disruption???

[Royal]

Originally Posted by camille1585

I think your theory on equatorial plants is right as well, that moisture and temperature might be more important blooming triggers. But if we only look at photoperiod and nothing else,those further away from the equator respond to changes in photoperiod and those near the equator respond to constant photoperiod.

Of course, maybe both of us are completely off target or maybe making such generalizations is wrong!

I'm probably way off!

My thinking is that with the constant being the photoperiod, a plant must rely on other factors. There would be less of a chance that an equatorial orchid would rely on, and therefore be affected by, day length. Conversely, if the photoperiod is ever changing, a plant could theoretically become accustomed to, or rely on short or long days as a bloom signal.

[Ross]

So far, I haven't found any of mine to be particularly sensitive to photoperiod. I'm actually pretty lazy about cahnging the cycles on my light timers. I have, however, found that winter rest for certain dormant species (such as Dendrobium anosmum) is an absolute. I tend to get blooms pretty much any time of year. These blooms don't seem to hurt the plants at all. I've had a Beallara in constant bloom (still is in bloom with 3 spikes) for over 2 years. No resting period. I really don't think photoperiod is really a strong agent for many orchids. Now, if we are discussing raddish or lettuce, that's a whole different matter!

[RosieC]

Originally Posted by Leslie2934

What are a few varieties that are photoperiod sensitive. I mostly have phals, but I do have a few others. Just curious.

I've never come accross this idea, so my Phals have always just had whatever lights I turn on for my own use. From the consitent spiking I've got from my Phals I think those should be fine with whatever standard lights you turn on at night. (Of course growing lamps are another matter).

[Leslie2934]

Wow this has been a great discussion. I'm going to let my sister in law know that turning her lights on and off is not going to keep her plants from blooming. I have several phals in my dining room that are in bloom right now. But then that is also not a light that goes on everyday either. She made mention that the person that told her this won't even go into her greenhouse with a flashlight on. Hmmmm.

[rickbarber]

Guess what I did to my cat's. They ( 7 of them )are going on their third year from clippings from the parent plant. After 3 years of no flowers this summer I exposed my cat's on the south side with shade in evenings only. I covered them with a white sheet to keep them from burning. Then cut the light off by moving them into the garage for 6 weeks before I brought them in side the house because of the cold. Well taking away light forsed my first flower spikes in three years on 6 0f 7.

[Brooke]

Cattleya labiata is the only plant I know that responds to a reduction of light in the fall. It blooms in the late fall after the days get shorter.

I have a primary hybrid with labiata as one of the parents but it actually blooms whenever the new growths mature.

Brooke

[Royal]

Originally Posted by rickbarber

Guess what I did to my cat's. They ( 7 of them )are going on their third year from clippings from the parent plant. After 3 years of no flowers this summer I exposed my cat's on the south side with shade in evenings only. I covered them with a white sheet to keep them from burning. Then cut the light off by moving them into the garage for 6 weeks before I brought them in side the house because of the cold. Well taking away light forsed my first flower spikes in three years on 6 0f 7.

Do you mean complete darkness - 24hrs per day? That can stress a plant to the point of flowering for preservation. Could have been the cold, could have been the reduced temps, could have been a change in humidity, altered watering/fertilizer - so many variables.

I see a lot of my plants spike as the day shortens too. BUT, as the day is shortening temps go down. As they come inside or are otherwise accommodated over the winter, they get less water and fert, and lower humidity. All get shorter days, but some are getting more intense light while others barely get enough. When so many parameters change at once, it's difficult to attribute the blooms to just one thing.