Looks very healthy. Sometimes they drop their lower leaves when you change their growing conditions. Have you?

If not, it is likely normal. Phals drop their lower leaves, often before they put out new growth.

Your plant has healthy leaves and roots. The loss of lower leaves is typically nothing to worry about.

You need to show a pic of the crown. It could be crown rot which is caused by a fungal infection of the crown. Usually caused by water sitting in there.

Could you take a pic showing the other side of the plant?

Jane

Oh Jane's right. Now that Im looking at the pic, the yellow leaf is not a lower leaf at all.

Dont be shy ;-) this isnt facebook- you WANT to take a picture of the bad side. lol

Thanks so much. I was waiting for responses through email and didn't check in here promptly. I do have other pics but I couldn't load them all the first post. It did seem like there was spongy black rot in that place where the leaves emerge. I had wiped water off leaves but hadn't been careful enough perhaps of the crook of the leaves. I have now put some cinnamon there. Will try and post pic now. Thanks so much. I am hoping it will rally. Unfortunately now the stem of the flowers is turning quite brown and woody looking.Eeeeek!

Yep, that's crown rot. Pour some hydrogen peroxide in there, and when it is done bubbling turn the plant upside down to let it drain out of the crown. It looks pretty bad though. It may not come back...It's possible with so many healthy roots, you may get a basal keiki if you can stop the rot from progressing.

Thanks Lauraeli
I'm relieved after googling basal keiki that I'm not getting something worse than I started with, lol. I've done the peroxide now and I'll hope for the best. Will be very careful about watering the others from now on. I take it that's what happened, water got in the crown.

Yes, thats right. Always make sure the crown stays dry. Orchids do things very slowly so it may be a while before it decides to grow a keiki. Luckily you have some healthy orchids to care for while you wait.

great thread. yeah, crown rot, peroxide,lower the light, the spahgum moss is good for those who don't water often or need to drench with antifungal. Just kind of an as needed amendment, which is why you find it in stores on orchids, because the orchids might not get a drink. I have an update on mine. I lost a leaf myself from letting it get too dry up top, the leaf partially being attached, getting too much light and well the rest is photography. Which is what the op has going in addition to what looks like crown rot. Then dendrobiums got a rubbing alcohol and water drench after a lone spidermite made an appearance, this is how they held up, a week later. The phalaenopsis seems to really enjoy light on the backside of it's leaves most, idk. Looks like mine lived after all. Surprise.

Using Canada peat, of all things, check out these crowns. Amazing, no rot, I drenched them yesterday and gave it a fertilize. Just sharing to add a little cheer, in case a seedling didn't sprout in that crown. With crowns like the op has,I wonder sometimes if a seed will sprout without the lab like conditions in them. 3pics, 2 will follow.

two

three

I go two weeks without watering, now I have a leaf spot,but it is kind of woody, so,just a minor ding,no worse for the wear. fungal most likely,might sprout a seed. just a wait and see, by now it is already systemic or resistant. with the medium I have them growing in, neglect is best. mine might die, but I won't be out a bunch of money. simply put, they are epiphytes, all their roots are air roots, it is an air plant,but requires humidity and moisture, weak fertilizer, bright light and occasionally dry conditions. get a good balance of wet and dry in it's pot. if you enjoy orchids, learning about them gives you a way to challenge what's written a bit. lot of trial and error.

looking it up,seems a bite of the cold, a cold spot basically or mesophyll cellular collapse spot, below 45 degrees f can cause it. hmmmm... weeks after the cold source those can pop up. i just found it, now how did one spot take a bite and the rest fine? Odd. I don't do ice cubes. lol, it's a possible who dun it 'round here, now. lol. don't sweat it,it'll be fine.