Minimum Temperature for Phals

[james mickelso]

Yeah. I just was wondering. That's all. My phals grow well in winter and summer. Winter has 10-20 degree diff night to day but summer has almost none and they still bloom. I know growers vary the temps quite a bit when they are ready to market their phals all at once. But most flower when they have stored enough energy to do so. Just wondering. Good culture for the home hobbyist is more important. Phals grow naturally in very warm and humid conditions with very little temp variation. And still bloom well. Again some more than others. Probably depends on what the parents were.

[Ray]

Cool nights are not going to cause it to rebloom anyway.

Dr. Yin-Tung Wang showed in a Texas A&M study that it's a 10°-15°F reduction in average growing temperature that can force blooming, not a day/night change. If the plant has been grown hot for a while, and that day/night variation lowers the average sufficiently, it will work, but otherwise, that's not enough stimulus.

I tested that myself: Read this.

[Paul Mc]

Yup. Agreed Ray. I was just trying to keep it simple, lol... But good for everyone to hear and remember that info.


Paul McMahon
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[lexusnexus]

Wow! Thanks. Yeah, I was not really interested in forcing the bloom. I guess I misunderstood about the reason for temperature differences. I am more interested in allowing the plant to go through its natural life cycle rather than forcing it to bloom. I'll leave it where it is with the other phals.

[james mickelso]

Thanks Ray. Good info as usual.

[Ray]

I speculate - and you all know how much I like to do that - that the depression in temperature must be a precursor to the restoration of a warm, rainy period - a time when pollinators will hatch and start flying about looking for flowers. So in millions of years of evolution, the plants have learned to flower accordingly.

[james mickelso]

During the rainy season the orchids start their new growth and the pollinators are munchers. When the dry season comes the orchids flower and the pollinators become flyers. That's the normal succession anyway. The dry on the Asian mainland is created by high pressure over the interior of the continent which produces cooler temps and during the monsoon rainy season the warm air from the tropics lifts up the valleys into the central areas of the landmass. That is when the heat from the tropics is carried into the landmass. And it rains and rains.

[Paul Mc]

Wow! Didn't know that! Interesting...


Paul McMahon
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[jai_star]

The key to rebloom is a strong Phal that has recieved plenty of bright indirect light. Although my Phals have gotten used to minimal amounts of direct sun. Fertiliser is important but not critical and I dont feed every watering. When blooming is required place the Phals in an outdoor enclosure to protect fron rain and strong winds. But the temperature should be the same as outdoors. Fall time is when there is a 10 - 12 degrees flutuation its the balmy night that set the spikes. GOOD LUCK ALL. PM me for more info regarding Phals im good at them