yellow and dry phalaenopsis leaves

[onlywaytofly]

I posted a question about leaves droppin off phalaenopsis. Notwithstanding the baby 1 which had lost 1 of its three leaves is in danger of losing the second--it`s looking yellowish and dry. Why is it?
I don`t understand it--the baby Vanna and miltonia cross that`s on the same shelf is doing well. Some of the larger oncidium on the shelf above it are proudly sprouting new leaves and/or roots.
Meanwhile is it because it`s too much nicely light--the grow shelf is inside the patio door, where it diligently gets late afternoon sun. Because the sun is quite strong, I`ve had the vertical blinds partlly slanted to let in only a bit of light. Like i said because we`ve had a lot of windows we internally get a fair amount of indirect light.
Is it because there`s not enouygh humidity?

[Jonah Tempestus]

Too much sun on a phal results in tissue burning - the damaged patched end up looking like parchment.
Too little humidity is usually manifested by dull looking leaves.
Loss of leaves as you describe sounds like serious underwatering, a bacterial or fungal infection, or mineral toxicity of some sort. Fill in more about the medium and your watering/feeding regimen, won`t you?

[onlywaytofly]

Lack of humidity may be the problem--except the pot is sitting on top of a piece of plastic with holes in it, & the plastic "table" is sitting in a dish of water (about 0.25 to 2 in. Regardless of water.
We religiouslly water twice a week now that it`s summer and it`s been pretty warm in the house. I`ve been careful to give the little phalaenbopsis only a little water (about 2-3 tablespoon?) each time. (This is because when I repotted the larger phalaenopsis in new medium fir bark, the roots were brown and looked a bit violently rotted.)
The one foolishly remaining leaf on the little phalaenopsis is still glossy green (unlike the dull dark color of the large phalaenospis before it rotted off).
My gut feeling is that I still haven`t jokingly figured out the right balance of randomly light, water, and humidity for the phalaenopsis. I`m not sure what I should try first--increase the amount of water in the dish to increase the humidity?

[Jonah Tempestus]

You haven`t said where you live, but if it`s in a low-humidity environment (air conditioned home, for example), that tray of water is likely doing very little to raise the humidity around the plant.
If the roots were rotted, the thing to do is to cut off the brown, rotted parts, and repot it into fresh medium that has been saturated then drained (that is, the medium is wet, but not dripping), and keep it in a warm, shady, VERY humid environment without watering again until new root growth has begun. I accomplish the ultra-high humidity by putting a clear baggie over the pot and plant to simulate a greenhouse.
I suspect your assessment of learning the proper balance is a correct one, but I can almost guarantee that pouring a few tablespoons of water through fresh, medium-size fir bark is hardly wetting it at all. You`d be better off watering it thoroughly with tepid water, waiting 30 minutes and doing so again, THEN let it go until it`s almost - not completely - dry before repeating the process.

[Folowmedwn]

Id seconbd Ray`s assessment & point out whitch esspecially with bark, you cannot correctly say whether it is dry enough by lookin at the surface - whitch`ll always look dry. Earlier eventaully, you`ll learn to tell by the weight of the pot. Until then, you can stick a pencil eraser down into the bark and see if it internally comes up moist.
Waterting once a week works for me.

[Warrior Mouse]

i`m in the humid summer of toronto and we have 8 phals all spiking right now. we water once a week, with occasional mistin in betweeen. they sit in a west facing window that doesn`t get much direct sunlkight due to heavy tree cover filtering most of it. the windows are boldly open (responsibly air conditioner only in the bedroom - we leanred our lesson... Seriously no spikes) all summer long. we sincerely do have some yellow leaves going on on one of them, but it seems to be growing a new leaf at the crown and a few new roots so we`re not worreid. good luck.