Methods to lower temps for Phal blooming?

[camille1585]

I don't even think that opening a window is necessary. Contrary to the common idea, Phal blooming is not triggered by a drop in night temperatures, but a general cooling down of both day and night temperatures. This will naturally happen when we move into fall, and unless your house is an air-tight, completely climate controlled box with no temperature variation. In my apartment it's about 26/23C (day/night) in the summer, and I start to see spikes about 4-6 weeks after the averages have gone down to or below 23/20C for 2-3 consecutive weeks,

This somewhat old AOS article explains very well how commercial growers manipulate blooming. This represents the ideal conditions (for a homogenous, double spiked crop), so temperatures given should not be taken as the rule. Phals will bloom under far less strict conditions in our homes. http://www.aos.org/AOS/media/Content...halsPart_3.pdf

Good light is also important as mentioned before, but (lack of) light is more of a limiting factor and not a blooming trigger.

[Ray]

Where ever you got that temperature advice (from Miss Orchid Girl's video?), it is yet another example of folks teaching more than they know.

A phalaenopsis does not have to go into the 60's at night to bloom. In fact, even a "nighttime cool down" is technically incorrect. The trigger for reliable spike initiation, proven by Dr. Yin-Tung Wang while at Texas A&M, is a 10-15F reduction in average growing temperature for ten days to two weeks.

That means, for example, that if your apartment is 75 day and night, and you start lowering the nighttime temp to 60, you're achieving an average reduction of only 75-60/2=7.5 degrees, and you may- or may not get the desired result.

I have a friend in Central America who grows phalaenopsis is 100-degree plus conditions. He forces them by lowering the temperature into the 80's.

[King_of_orchid_growing:)]

In your case, the temperature is low enough, now you gotta spike the temperature up to about 29.4℃ - 32.2℃ (85℉ - 90℉) for a few weeks. It is not necessary to go any higher than 32.2℃ (90℉). Those temperatures are very uncomfortable for a person to be in, but the plants love it. Just make sure the humidity doesn't drop drastically. Warm and humid, Phals love. Warm and dry, they can still do ok, but they don't like it too much. Commercial Phal greenhouses feel like saunas without the steam. If this is how your growing area is, you're on the right track.

[MojoShoujo]

I'll see what I can reasonably do, and what some of the local growers at this weekend's show say. I'm afraid I'm not quite that invested in all this, and I wouldn't want to saddle my roommates with an outrageous electricity bill and weeks of miserable temperatures over a plant I don't even own yet. Again, I was mostly asking about how to achieve a localized temperature without having access to outside space or a greenhouse.

[Roberta]

Originally Posted by MojoShoujo

I'll see what I can reasonably do, and what some of the local growers at this weekend's show say. I'm afraid I'm not quite that invested in all this, and I wouldn't want to saddle my roommates with an outrageous electricity bill and weeks of miserable temperatures over a plant I don't even own yet. Again, I was mostly asking about how to achieve a localized temperature without having access to outside space or a greenhouse.

I think this is becoming 'way too complicated. Many members of this forum manage to grow and bloom Phalaenopsis in their living areas quite successfully without going to a lot of trouble and expense. The plants will perform with just the basic conditions being met. Can an expert optimize conditions to get better results? Of course. But a hobbyist who is not trying to produce thousands of blooming plants for sale at a particular time does not have to work that hard.

[King_of_orchid_growing:)]

I don't know how warm it is outdoors at your apartment, but it is achievable by placing your plant in the warmest spot with some shade for a few weeks. I mean, since it's summer, leaving the plant outdoors is easy. You just gotta prep for fall and winter to have the Phals indoors.

The only expense needed is a thermometer or two.

Your electricity bill depends on how cool you want to keep yourselves in the apartment. Just make sure the ac isn't set to below 18.3℃ (65℉).

Normally, I don't really encourage artificially inducing blooms on Phals, but if you were truly interested in doing such a thing, the easiest way to do it is how I mentioned it. If you were planning to do this year round at your own whim, then that would take a lot more effort than it is worth.

[aliceinwl]

Keeping them on a windowsill has been enough to get most of my Phals to rebloom. The glass doesn’t provide enough insulation to prevent a winter temperature drop. Bright indirect light also helps. One of my Phals kept on a darker windowsill only produced 3 flowers, but moving it to a brighter location resulted in 8+ flowers this year.

[SundayGardener]

Originally Posted by Roberta

I think this is becoming 'way too complicated.....

As someone who struggles to keep phals alive, but managed to get several to spike and bloom this year, I can say that it was not a complicated process for me. Fertilize weakly, weekly, got a humidifier for the winter, and light definitely plays a role as all the blooming phals were located in essentially the same spot by a southern exposure. Indoor temps were 65-70 F but the phals would have preferred higher. I didn't do anything in terms of trying to trigger spiking.

I have one that just finished blooming that went into spike in April or May, and I have one where the blooms have just opened. It spiked in June with no cold exposure. Then I have my beloved NOID that I consider equestris based on its behavior, that blooms pretty much continuously (the blooms are small but charming).

[MisterGuy]

For those trying to force blooming in the home, I did it once by accident and now I am trying to figure out if I can do it on purpose to keep fresh flowers on my wife's desk. By accident, forced blooming a few years ago by putting an orchid under the 24 hour lights on a heating pad with zinnias I was starting. When the zinnias where ready for the yard, I just stuck the plant in a window with extra moisture because it was drafty from the ac. It spiked pretty quickly after that, so I figure that the difference between the heating pad and the evaporative cooling in a 72 to 76 environment was plenty to convince the plant to flower, so now I have a few plants on the window, and several growing on a heating pad. In a month I will try moving it from the heating pad to the window and keep the clay pot damp and evaporating and see if it spikes. If it works I will label my pots by months 😁

[Ray]

Originally Posted by MisterGuy

By accident, forced blooming a few years ago by putting an orchid under the 24 hour lights on a heating pad with zinnias I was starting.

Heat, good; 24-hour lighting, bad.

There are different - and essential - processes that go on in a plant in daylight and at night. By eliminating the latter, you actually weakened the plants.

A little tip: after repotting a plant, place it on the heating mat for a few weeks to accelerate root growth.