Temperature variation for Phrags

[abax]

I have been under the perhaps mistaken idea that most orchids including
Phrags. require a day/night temperature shift of 10F-15F to promote
blooming. In fact to grow orchids well at all. Any discussion?

 

[monocotman]

Mine get less than that all winter. Days are about 65f and nights high 50’s. They seem to do fine,
David

 

[Ray]

Looking at the Baker's data published in Orchid Wiz, the diurnal rage for the species ranges from 8°-9°F for sargentianum, up to 23°-27°F for caudatum, with most being in the range you suggested. However, who said that has a direct effect on blooming? My collection is stuck at 72° in the house, and I have Phrag. Sorcerer's Apprentice and QF Aloha in bloom, with a Paph. venustum bud emerging.

 

[tomkalina]

Our diurnal range runs from 10-15F depending on the season, so I don't see any problem with your temps.

 

[abax]

Seems I read that long ago in the AOS mag. Just
wondering if the research has been validated recently.
The success of growers without such temperature
variation do very well. Ray and David being good
examples.

 

[monocotman]

There may be a difference for this trait between wild collected species plants that have been selected in the wild for an ability to cope with temperature swings and either hybrid or species developed in greenhouses where the conditions are very different.
David

 

[Ray]

Usually, it is somewhat cooler at night.

There are different chemical reactions that take place in a plant in sunlight and when it is in the dark.

The relative rates of those reactions likely affect growth rates, flowering, and overall health.

Chemical reaction rates can be affected by temperature.

So it seems to me that diurnal differences can affect our plants, but it’s just another of the myriad of cultural parameters that determine how our plants perform versus the “ideal” situation. It is a factor I have little control over it, so typically don’t even think about it.

 

[abax]

Why indeed? The successful growing/blooming
of both you and David intrigue me. I realize
that temps. are not absolute rules...just general
guidelines. I have been following these AOS guidelines
for years. Now I wonder if all that effort might have
been unnecessary.

 

[monocotman]

I agree with Ray. We have a set of cultural parameters set by orchid growers across the years but knowing which ones are strictly necessary and which are ‘nice to haves’ in your particular situation is an unknown. It’s the same for everyone else. The joy of orchid growing is finding out what yours are.
The holy cow that is ‘thou shalt only grow good orchids in a moist buoyant atmosphere with plenty of air movement’ is another case in point. It may be a council of perfection but what conditions can orchids actually tolerate and still grow ok?
I have no noticeable air movement and my phrags and catts do fine on windowsills. The phrags do ok outside in the summer and there they do get air movement but there is no noticeable improvement in growth.
The good growers observe their plants closely on an almost daily basis.
They make small changes to some part of the environment looking for improvements and then see how things go.
This is the art of orchid growing.
David

 

[abax]

Exactly!