Extra long spike, few flowers
 

Hello Everyone,

Bought this Phal two years ago, was planted in sphagnum moss; moved it to S/H right away and it thrived; the phal came with two flower spikes.

It has been growing new leaves and roots ever since I moved it; flush + fertilize + Kelpmax regularly. It has 15 leaves.

This year two spikes started to emerge, after a while, and when they reached about 15 cm in length, they stopped growing and a third spike emerged; length more than 65 cm and only a few flowers seem to be appearing.

Any help from the experts on the matter, am I doing anything wrong?

Strange... My first thought is that maybe it's not getting a long enough cool period. Phals are quite sensitive to temperature, and need to remain at temperatures lower than 26 C / 79 F for four to five weeks in order to put out a spike.

If that plant is subjected to higher temperatures, 28 C / 82 F for even as little as 8-12 hours before the blooms open, it can stop a spike from blooming. High temperatures can cause a spike to elongate and produce less flowers, and possibly a keiki.

Here are some articles to read, if you're interested:
Optimal flowering temps
Inhibition of flowering

---------- Post added at 09:43 AM ---------- Previous post was at 09:39 AM ----------

I have found with my own phals, though, that if I put them through a cool period while they are currently in flower, they will frequently produce more flowers on the same spike without any other effort on my part.

So, try cooling it down! I really hope it works, because that plant is just gorgeous! I would love to have a peach-colored phal like that one!

How do you maintain a water reservoir with that pot? Does it sit inside another container?

Thank you very much for your help; this is another Phal with the same growing condition and care...
I am just going to let it be and see where this is going to lead to.

Nope, the reservoir is at the bottom of the same pot.

Okay, so can you regulate the amount (depth) of water in the pot/reservoir?

I am not sure I understand what you mean; but it is a standard pot which I turned into a semi-hydro pot, 2 side holes at about 2 inches high from the bottom.

The plants are always flushed when watered, and the bottom reservoirs are always almost full.

Got it! At first the pot looked like a standard pot. I think Phals are the least tolerant orchid for any S/H errors. Mine did "fine" in S/H but really started to thrive when I put them in wooden baskets with the clay pellets. I water more often of course, but they really like their airier environment. That strange spike aside, yours seem to happy in their S/H environment.

P.S., In S/H I had a lot of "aerial roots" but no such thing now in the LECA and baskets. Maybe before they were trying to climb out of their S/H environment ;-)

Regarding your original post, I have experienced a similar problem. I don't have a definitive answer, but my current theory is too much nitrogen/fertilizer while the spike was developing.

For quite a while, I had many young plants with a lot of growing to do before blooming, so I used a high nitrogen fertilizer to promote growth. I have recently switched to a so-callef "bloom boost" formulation where N is lower relative to P and K (11-35-15, I think). I used to provide fertilizer weekly, at 1/4 the recommended strength, now it's more like 1/4 strength once or twice a month. From what I've read, I think the lower N fuels less vegetative growth, allowing more flower production from a well-nourished plant. Has nothing to do with having more P in the fertilizer. You could probably achieve the same thing by just using fertilizer less often or at even lower strength.

So far, Phals that have put out spikes since I changed fertilizer regime are not leggy and have more flowers per spike.

So, that's my working theory . . . or I could be completely full of crap. I want to see the rest of my Phals flower before claiming victory.