Why would a healthy phal drop 4 of its 6 leaves?
 

Even though I've been growing orchids successfully for several years, I'm posting this in the Beginner's section because, well, I feel like a beginner and its a common problem: unexplained leaf loss of Phalaenopsis.

I bought a blooming, well-grown Phal recently. When it finished blooming, I didn't repot right away because I could see several thick, healthy green roots. Well, within a week, four of its six leaves began the "I'm gonna turn yellow and eventually fall off" thing. So, my first thought was "Uh oh, root problem." So I unpotted it, expecting to see rotten roots, but it has tons of thick, firm roots with no visible rotting on the roots or stem.

So why on earth would it drop so many leaves at once? I have several Phals. in the same growing conditions that are doing just fine. And if its some kind of disease, there are no visual signs of it. I just get frustrated when a well-cared-for plant suddenly decides to commit suicide.

Any ideas? Thanks.

it might be mechanical....while in transit the plant got dropped while inside the box; the four leaves got pressed and bent from its base and the trauma was not felt until the time you got it at home where the plant got relaxed got unbent and unpressed then the damage finally went on its course and the leaf yellowed and dropped. If it was bacteria or fungi=you will have proof of the infestation on the surviving leaves left....pictures would have been a great help especially the cut portion where the leaves left the stem.

This could owe to some bacterial infection not yet visible/evident. Perhaps the start of crown rot? If so, it could have initially look well grown, but under it all, hosting some disease which is now progressing visibly.

Also possible the plant was forced in the commercial greenhouse whence it came. After all, huge, commercial breeders/growers for the mass market, get, their target customer is far too often, only interested in the living equivalent of having cut flowers.

I'm curious as to why forcing the plant to bloom would make it drop leaves. Is this what you mean by "forced," as in manipulating temperature? Does this cause problems for plants?

Artificially inducing the orchid to bloom repeatedly, can cause problems and affect the orchid's health negatively in the long run.

How're you growing the problematic Phal, and what kind of Phal is it?

Can you provide photos of it?

I don't have any photos because I wound up throwing it away, a loss of $12. If it was disease, I don't want it spreading. However, before I tossed it, I decided to donate its body to science. I sliced off the remaining leaves and dissected the stem, looking for signs of infection or decay. But the plant tissue was turgid and healthy with no rot.

The only thing I can think of is that the transition from store to home was somehow overly stressful, possibly humidity-wise, and the plant dropped all its leaves to prevent water loss through leaf transpiration.

Hard to tell without photos but I'm leaning toward the bacterial rot theory.

It was probably from heavy amounts of stress not disease, if you're saying that all tissue was turgid and there were no signs of rotting.

It would've been able to recover after a few years.

I've had Phals do this before.

In fact, I just posted a couple of pics of Phals that did this in my own collection about a few weeks ago, and I also posted pics to show how they were growing back new leaves.

I can post a more updated photo of the same 2 Phals today on your thread right now to show you.

This happens more frequently than you think with Phals.

To give you an idea, I didn't purchase these as seedlings, nor were they purchased in this condition for saving, (I don't like saving orchids from the get-go if I can help it, it can be incredibly time consuming, stressful, and expensive for me). They were near blooming sized plants.

The one on the left is Phalaenopsis lindenii. I originally had 2 plants, only 1 made it. Both plants had beautiful mottled leaves. However, sometime after I purchased them they had become heavily infested with scale several times. Eventually, both plants dropped all their leaves, and the only thing left behind were some roots and a portion of their stems covered by the dried up petioles. This was the only one that made it out of that ordeal, and has come back to give me what you see. There is no mottling on the leaves at current, but with each new leaf produced, the mottling will return.

The orchid on the right is Phal stuartiana. This one mysteriously dropped its leaves slowly, one-by-one. Had a strong root system and everything. This was definitely a stress related problem. Between dropping leaves, it also produced new ones. These are the new leaves. Again, the mottling doesn't show up with these new leaves, but there are subtle hints of them that may not show up on the photo clearly. With each new leaf, I have confidence that it will produce the mottling again.

The same 2 orchids a few weeks ago are in the photo on the right.

Phals have the ability to do this. I've never once said that Phals were easy, and this is one of the reasons why. They will always present a challenge even if you think you are the most seasoned veteran in orchid growing. I don't ever recommend Phals for total beginners because of how tricky they can be to grow. It is true that some Phals are easier to grow than others, but in general they are not, imo, great for total newbies. Imo, there are far easier orchids to grow than Phals, and there are tons of them that are just as exotic, if not, more so. My opinion is of that Phals are generally better suited for those who have been growing orchids for at least 3 years or more. Do not feel bad, you're not alone.