Problem with Phal.

[AndreasDK]

I have an orchid that has lost many leaves.

The start out fine, grow to a large size and then they develop these marks that escalate during a month or so. other places on the same leaf becomes yellowish and sort of like transparent (hard to photograph but I have given it a shot).

Does anyone know what the problem can be?

[King_of_orchid_growing:)]

It's difficult to tell.

Can you give us more information about your cultural parameters, cultural habits, cultural techniques? Without them, it's hard to tell you what to make adjustments with.

How bright are you growing it? Clues such as your best verbal description, a photo of where you grow it, or the direction the window is facing are helpful. Even better would be a light meter reading in either lux, lumens, or footcandles (footcandles being the more commonly used unit of measurement in orchid growing).

Temperatures? Night/day/seasonal?

Humidity?

How are the roots? Pics please.

How often do you water?

How are you watering?

What's the potting medium?

Do you change out the medium?