Question about dropping leaves
 

Morning, everyone!

I am curious as to what makes orchids drop leaves, in this case specifically phals. I've got a big NoID phal in my living room window and it's dropping its bottom leaf (which is it's now bottom leaf...it already dropped its very bottom one which was located on the other side of its crown). It started putting out a new leaf and then just kind of....stopped.

Next to it is a mini Phal. Timothy Christopher, who is also dropping its lowest leaf.

And then in my kitchen, a totally different part of the house, one of my mini NoID gift phals started putting out a new leaf, stopped growing it, and is instead dropping its lower leaf and growing new roots...

What are they doing and why? And is this something in my environment that I need to fix? Or is it because it was hot this week? My kitchen stays much warmer and more humid than does my living room where the other phals are, so I am confused.

Interesting question. First, phals have no pbulbs in which to store moisture/starches/sugars and so use their leaves for this. Sometimes they will use up their store of fat in a leaf and shed it because they don't need it anymore and don't hold on to something that isn't needed. It doesn't support something of no value. Sometimes it drops a leaf because of environmental stress. The root system can't support all of the vegetative mass. Sometimes the plant will start to grow a new leaf and due to that same stress it will stop using resources to grow the new leaf while it waits for the environment to stabilize. Sometimes it's just time to rest. Without knowing what it is doing we just have to watch and wait while it slowly evolves. It's been hot there so it may have been in the process of renewal and stopped to wait. Don't overwater now especially because it may be under some duress and needs to slow down for a bit. Just keep it damp. Orchids are ....S...L...O...W... if nothing else.

I dunked everyone's pots in some KelpMax I received from Ray when it was their turn to be watered just a few days ago, and I generally wait 4-5 days before I check them (especially my ones in the kitchen, they stay more humid than the rest because of their positioning close to my stove)...I am hoping that helps them, at least in the way of continuing to grow. I don't water them unless they're showing that their roots are silver and their media is dry..and I've got skewers in. I recently repotted everyone into a mix of sphag and bark (with the temps rising the bark by itself was drying out much faster than I could keep up with)...could that be it? Are they just trying to adjust to that?

I will just wait and see.

Repotting is stressful to orchids. You can repot very carefully and everything is ok but then you can be very careful and things go awry. The act of taking the orchid out of the environment it is used to and changing the conditions it is used to induces stress and also causes tiny cracks in the velamin around the roots which allows water to escape. And just the act of bending the root back and forth causes these tiny cracks in the roots themselves. Best to repot an orchid dry than when it is full of water. Changing the environment also changes things like pH. But orchids are resilient if nothing else. With sphagnum moss mixed in with the other media be careful to not keep them too wet. The moss holds moisture for an incredible amount of time. Moisture is ok but not wet. I would like you to try a little experiment. Let the orchids dry out for an extra day or two. Until you are sure they are as dry as can be. Before you water them, lift them up and feel how light they are. Get a good feel for their weight. Now water them really well. Now lift them up and judge their weight. Really get a feel for how heavy they are. Lift them a couple time during the day. Now let them dry really well again. In a few days lift them up and feel how light they are. When you have judged them to be really dry again, water them and feel the difference. You'll be amazed now how well you can judge when they need to be watered. You'll be able to walk by them at any time and know when they need water. Your hand is very adept at noticing the difference. Better than your fingers or lips.

I have been trying to learn that, I have gotten good at it with the cattleya types, lol. And when in doubt, I just wait a few days longer. Just to be sure. And if I even doubt that, I feel the skewer.