Phal flower spikes very short

[opulenceflowers]

My Phal is starting to bloom which is still our winter in Cape Town. It is forming the flower spikes very short and some are bunching so much that there is not enough room for flowers to open. I do believe that the evenings are too cold in my greenhouse (around 13deg Celsius), but is this the only reason, or can it be lighting or too much feeeding (nit is half strength, but kept it up during winter) The greenhouse has a 70% shading all round and on top. I attach photo's. Second issue is that the plant is making very fat aerial roots - is this a sign of unhappiness?

[RosieC]

Some Phals do have shorter stems than others, and some hybrids have the flowers bunched too tightly for the size of flower (due to breading).

But I'm not sure that is the case with yours. The leaves also look somewhat stunted on all of yours.

I think 13C is too cold for most Phals so this could be a factor but I'm not sure.

Arial roots are not a problem as such on Phals BUT the medium in the last pic looks very broken down. It could be that the roots in the pot are dead/dying and the arial roots have grown to replace them.

Again I'm not sure so hopefully others will chime in with their advise.

[Undergrounder]

I think your Phals are showing general signs of being deeply unhappy.. the flower spikes - i wouldn't worry about them too much, they might sort themselves out when the rest of the plant cheers up a bit.

What's the humidity like in the greenhouse? Those aerial roots have grown about an inch, then stopped growing instantly. They should be a lot longer than that. This could be due to both the cold temps or a lack of humidity, but they've been doing that for a while - longer than the last 4 months of winter.

13 degrees is too cold, and that could be a factor. It might not be too cold to cause damage, but it's definitely cold enough to stunt growth and make them unhappy. But again, it looks like the plants have been unhappy for a lot longer than just this last winter.

I wouldn't use -any- fertiliser now, they're not in growth mode and they won't be until it's a lot warmer.

But the most worrying sign is that each of your new leaves are getting smaller and smaller. I think i can see this on all of the Phals in your photos. Plus, what leaves there are are floppy and wrinkled. These are signs that the plant isn't getting the water it needs, and it hasn't been happy for a long time.. The newest leaf (at the top) will always grow to a size indicative of the root system. Those top leaves are very small, so i doubt you have any roots at all down there under the media. They've probably all died off, stimulating the new root growth that RosieC was talking about.

Just about the best thing you could do for them is repot them into fresh, chunky media. I would repot everything you have in that wet peat/sphag/perlite mix you've got while you're at it, even if it's not really showing signs of problems yet. Then i would see if you can't up the humidity, or down the air movement. Don't use fertiliser for at least 6 months. Check your light levels too, 70% is quite possibly too low, especially in winter.

Whatever you do, judging by the size of those top leaves, it's going to take at least a year for them to recover.. if you can get new root growth during the summer, and direct it into an airy, open mix that you keep well watered, then they'll be fine. Just keep an eye on those leaves, and if you -ever- get a top leaf that's smaller than the leaves below it, get onto it early!

good luck!

[RosieC]

Originally Posted by Undergrounder

Just keep an eye on those leaves, and if you -ever- get a top leaf that's smaller than the leaves below it, get onto it early!

:iagree: with everything Undergrounder has said, but especially that about the leaves.

That's the reason I thought the leaves looked stunted, the top leaves should not be that small compared the the lower leaves.

The only time I've had top leaves noticably smaller than the lower ones was on a Phal that I already knew had problems with it's roots. My healthy Phals seem to have leaves that get bigger with every one that emerges.

[King_of_orchid_growing:)]

1. The lowest it can be is 13 C (55 F). It shouldn't go any lower, this night time temperature is really pushing the plants to their limits. Ideally, the low end of the temperature range should be around 16 C (60 F). 13 C does have the potential to cause damage like Undergrounder had mentioned.

2. Like RosieC had mentioned, the potting media looks pretty broken down. The moss on top of the bark looks very crusty and the bark itself is almost black. If you pick up a piece of the bark and you can mush it around between your fingers and it leaves behind some debris; it needs a change. Another way to tell is if you're watering heavily and the water draining out has some debris coming out with it.

3. Like RosieC had said, because of how broken down the potting media is, there could be some damage done to the older root system. I highly recommend you check it out.

4. The leaves do appear stunted, I imagine it may be a combination of low night time temperatures, and insufficient water available to the plant, quite possibly due to either root loss or underwatering...

Which brings me to the question:

How often do you water?

5. The new roots are fine, just needs a repot.

[opulenceflowers]

Thank you for the advice. I water every week in winter. In summer i water a second time a week by just washing down the leaves and not watering the media. All these plants were in all sphagnum medium since I bought them. I then read on orchid board that I should have changed media long time ago. The photo's you see is the replanting into new media, allthough I am aware that the pine bark is not the best available, but stone pine bark has become impossible to obtain in Cape Town.

Regards
Roelof