Do summer blooming Phals need the fall cool nights?
 

As we are approaching the fall season here, I have read that to get the winter/spring blooming Phals to spike they need a period of 3-4 weeks of 55-60F nights.

My question is for summer blooming Phals, like violacea. Do they also need this cool time? or would that be bad for them?

I have a cooler room in my basement I can move them to if necessary, but I don't want to harm them.

Thanks

It's not the exact 55-60F temp it's the 15-20 degree difference between day and night that triggers spiking in the ones sensitive to that.

There are so many species as well as hybrids that there is no specific way to bloom them all. Back in my beginning days I would take all 20 or so up to my spare bedroom each night and bring them back down in the morning to get the temp difference. Didn't harm any of them and also didn't work on all of them ! I never chilled my violacea. You should research yours to find out.
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In my experience (14 months and 60+ Phals), they don't need a temperature drop at night, they just need the temperature not to go over 24C (75F). I've read this somewhere (can't remember where), and it's consistent with what I've been experiencing. All my Phals have reflowered - and I grow the whole range: species, primary hybrids, novelties, and standard hybrids (both named and noID). My temperature is 19-24C (66-75F) 99% of the time.

Val, that's wonderful that all yours rebloomed for you. In my experience (7 years, only 23 Phals right now) it takes longer than 2 years for some plants to adapt to a different environment. Tell me how they're doing after 3+ seasons in your care. I wish you luck !

Chryss

Huh? Many species Phals are hot growing. Meaning they like day temps well over 75F.

I can tell you that my Phals are all kept in my house where the temp is set at 76 before the a/c comes on. Many of mine are summer blooming, many are fall/winter/spring blooming that need the shorter hours, and a larger diurnal temp change to induce spiking.

Then I won't mention that my house averages in the 80s and gets to the 90s during the summer months and I've had no trouble blooming my Phals for 7 years !

You didn't hear that from me !!! LOL !!

Chryss

It's not a lower night temperature, nor a strong difference between night and day temperatures that induce phals. It's an overall reduction of BOTH day and night temperatures or keeping the plants under a certain temperature threshold. I visited a commercial orchid grower during college in the Netherlands, and that's what the grower explained to us.

I had also dug this up in a growing manual a few years ago:
"Phalaenopsis are induced to flower when exposed to temperatures lower than 79 F (26 C), particularly during
the day. Traditionally, growers use a 77 F/68 F day/night (25 C/20 C) temperature regimen for spike initiation. However, studies at Texas A&M University have shown that mature phalaenopsis can spike at constant day/night temperatures at or below 77 F (25 C). In fact, plants spike faster at a constant 25 C than at
20 C.
The production of phalaenopsis orchids can be divided into three phases:
Phase 1. Vegetative cultivation at high temperatures of 82 to 90 F (28 to 32 C)
Phase 2. Spike induction at low day temperatures of 63 to 77 F (17 to 25 C)
Phase 3. Finishing at 63 to 79 F (17 to 26 C)."

As for Phal violacea, being a species I'm not sure if this applies to it or not. I had a look in orchidwiz, and in its natural habitat there is very little variation in temperature throughout the year. In the summer it's in the high 80s during the day, and low 70s at night. The winter temps are only a few degress cooler. So I would just continue caring for it as you have, if it has been blooming well for you.

Thank you all for the information and comments.
Bob

To the original poster and question...no, hot growing summer blooming Phals do not need a cool down to initiate spiking. They just do their thing whenever they feel like it.

Thanks Terri, I am trying to learn and keep finding out that I don't know very much in regards to the Phals and other Chids at all. I'd like to not kill them all.