Question
QUESTION: Hello!  I'm new to orchids and bought my first two in mid-December.  Both looked fantastic - in flower, healthy looking green leaves.  Since then, I have cared for both in exactly the same manner, watering about once a week, keeping them in indirect light.  The white one is thriving, but the purple is not!  About a week ago, the two huge leaves on top began to turn yellow, from the "trunk" outward.  (please feel free to correct my use of the word trunk - it's the only way I can think to describe it)  They have now fallen off (I'm mortified!) and despite stopping watering (I read that I could be overwatering) the remaining two smaller leaves (that were underneath the large ones) are now turning yellow in the same manner!  I'm terrified I'm going to lose it.  The roots are somewhat exposed on top, and it seems to be potted almost entirely in bark.  The roots overall look very good - white and light green in the bark (it's a clear container, which is set in an opaque pot), and silvery-white on the parts above the bark, exposed to direct air.  Actually, looking at it now, some of those coming out of the trunk area (and exposed to the air on top) are now looking dark brown and are completely drying out.  This confuses me if the yellowing occured due to overwatering, yet these roots seem to be shrivelling from a lack of water.  (???)  I should explain that I felt I might be overwatering when I discovered that the inner pot was indeed sitting in water at the bottom of the outer pot - but then I let it dry out completely for over a week and the leaves are continuing to turn yellow - and now the trunk is turning yellow as well!  Of the original 6 flowers, there are only two left.  The white orchid was also sitting in water (since I've treated them exactly the same), but as I said, it is doing very well.  (and don't worry, I drained the water off both plants as soon as I clued in)

They are kept in a room that's about 70 degrees most of the time, and I have hard water.  I have not tried feeding them yet.

Please let me know if you need any more info.  Any help would be hugely appreciated!!

~Barb

ANSWER: Barb, thanks for the detail with your question.  I recommmend thaat you remove your plants from their pot and rinse off the roots.  This will enable you to make a detailed assessment of their health.  If one or more are mushy (ie outer root sheath has collapsed),  you will have identified the reason for the leaf problem.  Whle you did well to dry out the plant, once the root damage has occurred, it cannot be  reversed.  However, it is possible, by repotting in fresh orchid potting mix, to grow new roots and leaves.  This will take time.  Be sure you use a pot that has lots of drainage holes in the bottom.  Use an orchid potting mix that contains a medium grade of fir bark.  Wet it thoroughly prior to use as dry fir bark is water repellant.  The hard water and temperature are fine.  Try to let the water warm to room temperature before use and water in the morning.  For now, water only once per week.

---------- FOLLOW-UP ----------

QUESTION: Thank you SO much for such a quick and thorough reply!  I'll do all of that, and hopefully I can save it.  

Quick questions - the exposed roots at the top, above the bark, where they are brown and seem shrivelled and dry - can I assume they're dead and/or dying?  The brown part goes for about an inch, directly off the trunk, but then beyond that, the roots look greenish/white and healthy.  The trunk area is seriously worrying me now, as it is yellowing by the hour...  Also, when I repot it, should I be covering all the roots, or are the top ones supposed to be exposed like this?  The white (thriving) orchid seems to be more fully covered with bark.  Also, is it best to leave it just in the clear pot, or can I put that one back in the opaque one?  ie, do the roots care if they get light? (the opaque pot is more attractive, but if leaving it out is best, that's what I'll do)

Thank you again - I'm truly upset that this is happening, and am grateful for all advice.

Answer
Barb, roots above the potting mix that are firm are fine.  Usually, when they get wet, you will see some green in them.  Orchid roots photosynthesize, hence the green color is the chlorophyll. To this end, a clear pot permits light to get to the roots and that is fine.  If the pot has four or more drainage holes, that will help drain off excess moisture and allow the free movement of air through the root zone.

You are right to be concerned about yellowing of the "trunk".  If it is possible to remove he yellow part without sacrificing healthy tissue, do so and seal the open wound with powdered sulfur or cinnamon.

Feel free anytime to let me know if you have additional questions.  That's why I'm here.