Struggling to get phal position right

[Dalachin]

I grow in the northern us but under lights… in my experience, if a Phal is getting enough light, it will bloom, no temperature drop needed. Many bloom continuously, others once or twice a year, frequency seems to be based on genetics. I give mine a lot of light, probably comparable to a southern window with a sheer curtain. Some are in eastern facing windows, but I supplement that light with leds.

[Roberta]

I totally agree that light is likely the most important factor. The professionals control blooming with precise temperature drops (the Phal that blooms just before Mother's Day is more valuable than the one that blooms two weeks later) But when I started out in orchids, I was growing my Phals in a room with good morning light for 4-5 hours, then it became dimmer and indirect as the sun shifted. Few flowers. I put them under lights for 12 hours a day (I used cheap shop lights with full spectrum bulbs, no special grow bulbs needed) and got about 80% reblooming. I can't say for certain that temperature didn't have some involvement (in winter, the house was naturally cooler than in summer) but the difference was pretty minor.

[tmoney]

howdy! seems like a lot of good advice has already been given, but i gotta ask if you have repotted them, and when?

usually, when friends or family ask this exact thing (ive had a phal for years and its never rebloomed, what do i do?) i will tell them 3 simple things.

1. give it more light for at least 6 months to a year and see if it blooms.

2. try fertilising a bit more frequently. (usually the avg grower with one or 2 phals have never fertilised i have found). clearly this isn't your problem, so....

3. repot it, and see step 1.

if its a grocery store phal, generally it seems that the temp drops and seasonal fluctuations are enough if it is grown anywhere near a window. (if you have ultra modern insulated windows, well then perhaps it won't drop all that much in winter, but usually folks can find a colder room that is not heated and shove it next to a window in there for 5 months in the winter and see what happens.)

tl:dr yes, i think you have done the right thing. we've grown our phals in south or southeast full exposure and no burning issues. as long as you can keep it a little back from the window it shouldn't burn anything.

[Ray]

I think this is too complex of a situation to nail it to a single factor.

The average temperature drop has been shown to be a reliable way to force hybrids to bloom, which is why it is so useful and has led to the explosion of their sales.


However, that will work well with some species, but not others. A long time ago I observed that phalaenopsis species with primarily white/pink/purple flowers seemed to need that, while those with red/orange/yellow blossoms did not.

If you look at the geographic origins of the species, generally, that second group tends to be more equatorial than the first, so that makes sense, as the seasonal changes are practically nonexistent.

Light is certainly a factor, but I doubt it’s as straightforward as the temperature stuff.

Some of the best flowering phalaenopsis I’ve ever seen were grown in a hot, humid greenhouse that was so algae covered that it was dark. When I was a new grower and had not bought into “more light is better”, I had phalaenopsis that stayed in bloom for 6-, to 9 months at a time - they were grown in a windowless kitchen with the only light being a sliding glass door about 20 feet away.

Just this spring and summer, I observed something that would make me believe more light is better - after they have experienced a significant cool down period, my plants spend winters in my kitchen, up against north-facing, Low-E windows. Spikes were forming and growing slowly, until I moved them outside for the season, where they are located just outside those same windows, so get the same, indirect light, but more of it due to no glass-coating reduction and because they then had a bright, open sky above to add scattered light. They exploded into bloom and many continue carrying them now.

So how can “growing them dark” and “giving them more light” both be good?

[Putting on the biggest “speculation” hat I can find]

The only thing I can guess is that it relates to resource accumulation and the bit of adaptive ability the plants can muster.

Plants grown on the darker side always are darker green, courtesy of added chlorophyll, suggesting their metabolisms apparently adjust (within reason) to a lower-energy input lifestyle. With reduced input, I suspect they must accumulate a larger “storehouse” of phytochemical resources before blooming, but when they do…POW!…it is very well “fueled”.

Contrast that to a plant grown brighter. It has greater input and often moderates that by being paler, it with the input being steadier and faster, it can afford to bloom more often, albeit with less “fuel”, so can be smaller and relatively short-lived.

It also may be that those “privileged” plants, experiencing a steadier input, are less in need of a “seasonal trigger” to bloom, as they can afford to expend the resources more easily than can the darker-grown counterparts.