Phalaenopsis not Flowering

[Alan Sailer]

I have a collection of generic grocery store phals growing under LEDs at work. I have had many flowering events over the years with all the plants except one.

This plant stays dark green and has at least two offshoot growths that may be kekies. I added a second LED bulb that shines on this plant alone but still after several months it remains dark green.

Any ideas?

[rbarata]

From the photo it looks to be on the verge of "led burn".
Maybe it needs a seasonal temp drop to bloom.

[camille1585]

Given the color of the root tips and coloration of the rest of the plant, I'd guess that this is a dark colored flowering one? I agree that the light might be too much now, the leaf in the lower left side of the photo seems to show the type of mottling I've seen on Phals getting too much light under LEDs.

What are you fertilizing with, and how often?

Depending on where you are located, you could try sticking it outside in a sheltered spot for a month or so, so that it experiences a stronger temperature drop. As rbarata suggests, this one might need stronger seasonal variation if all else fails.

[Alan Sailer]

I'll consider that it might be getting too much light. The thing just looks so darn healthy. The photo does not do it justice.

I am using a very dilute fertilizer (maybe 5 times suggested strength) at every watering. The other phals have the same and currently three of eight are in bloom.

The day night temp variation is zero. They are in my office at work and they run temperature control all the time. This is a good suggestion so I will try taking it home and let it get some day/night variation. Finding a spot with suitable light will be hard in Southern California. It's just so hot and bright.

I am curious about the multiple growths. All the other phals have the typical monopodial growth, one "stem" adding leaves as it grows higher. This one has several growth nodes.

[MCD]

For some species multiple growths are common. Have you ever had that one bloom for you in the past? Maybe it has a lot of one of those in the background.

[Alan Sailer]

Only the original bloom long in the past.

I'll try a change in environment, it sounds like a very good idea to try.

Cheers.

[tmoney]

hey, i would bet that the non-varying temps are the culprit. but totally a guess. if it's with all the others in the same light then probly needs a cold bout.

we tried forcing a couple phals last winter and 2 months in the cold room made them flower pretty much right away. i think i remember ray or other mentioning that perhaps even less time would be needed.

i would try temp first, then try to find other variables if that doesn't do it

[Ray]

I can think of two possibilities: overfeeding and/or improper temperature profile.

I assume (hope) you meant you use the fertilizer at one-fifth the recommended concentration, not five times that, but that tells us nothing useful, anyway. What is the fertilizer formula and at what rate (ml/L, etc.) are you mixing it.

As far as temperature, it is not a day/night variation that is important. In order to reliably initiate an inflorescence, most phals need to experience about two weeks of a 10-15F reduction in the average temperature.

[tmoney]

Originally Posted by Ray

I can think of two possibilities: overfeeding and/or improper temperature profile.

I assume (hope) you meant you use the fertilizer at one-fifth the recommended concentration, not five times that, but that tells us nothing useful, anyway. What is the fertilizer formula and at what rate (ml/L, etc.) are you mixing it.

As far as temperature, it is not a day/night variation that is important. In order to reliably initiate an inflorescence, most phals need to experience about two weeks of a 10-15F reduction in the average temperature.

ahhh, 2 weeks was the number, thanks ray! and also, to the op, i am definitely in a questioning phase on fertilizing orchids. at this point i am not 100 convinced you really need to fertalize more than a couple times a year (for hybrid phals, i am talking)

i wouldn't think underfeeding is the cause, but certainly if you are giving them 5 times the strength it might....

[Ray]

Originally Posted by tmoney

at this point i am not 100 convinced you really need to fertalize more than a couple times a year (for hybrid phals, i am talking)

My small collection includes less than a dozen phals - bastianii, venosa and the rest hybrids, all in a LECA/rockwool cube blend. I intend to feed at 100 ppm N weekly, but I will admit that I have having difficulty doing that reliably, with other activities, so I'd guess I've probably been doing that, on average, every two weeks. With the heat, I've definitely kept up with the watering, so I know the calcium supply is adequate, at least.

The bottom line: it's not enough. The plant have done very little.

About four- to six weeks ago, I decided to raise that priority, actually feeding as planned, and they have all responded nicely, including the venosa and one of the hybrids blooming.