Question
QUESTION: Hi Jim,
I recently received a Dendrobium Burana Fancy that is in full bloom.  It was doing well for a while, but recently the leaves began getting small black spots, thinning and turning yellow one by one.  They then fall off.  I'm worried about losing them all if it's not supposed to.  I'm not sure if this plant is an evergreen or not.  There are a number of roots growing out at the base  of the plant and I've been watering once a week or less.  
Thanks for any insight you can give,
Liza
(I'm in Chicago - temps indoors are around 65-70 deg)
ANSWER: Hi Liza,

I'm not certain but believe your Dendrobium Burana Fancy is one of the evergreen types.  It would be unusual for an evergreen type to be losing its leaves at this time of the year, so there might be something else causing it.  

Growing indoors in Chicago, have you been also misting it and at what time of the day?  Misting is fine but should be done in the morning to allow any water droplets to evaporate by nightfall to prevent possible fungus growth on the leaves.  Do the black spots look a little sooty?  Is there a black sooty area at the base of the leaves where they had been attached to the plant?  If yes to one or both, it probably is fungus causing the leaves to fall off.  

To remedy this, clean off as much of the black areas as you can with a paper towel or Q-tips dipped in isopropyl alcohol.  You may not be able to get all of it off if the black fungus has been there for more than a few days.  

Try sniffing the potting media for the presence of a sour odor.  If it smells sour, that probably means the media has broken down and should be replaced.  

Hope this helps save your dendrobium.  If you find that it is not what I think is causing the leaf loss, write back and I'll try exploring some other possible causes.  

Jim Kawasaki
San Jose, Ca.

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

QUESTION: Jim,
I took a closer look at the dendrobium and the spots don't seem to grow or wipe off.  They are also appearing farther up the leaf, not so much at the base.  The leaves also dry out a little at a time until they just drop off.  I haven't misted this plant.  I have a few others that I've had for years that I don't mist and they have done beautifully, so I was trying to keep doing what seemed to be working with those.  Would it be beneficial to all my orchids to mist regularly?
I did notice that the roots are very dense in the pot, but I don't smell any sour odor.  Could it be that it's just not drying out enough between waterings?  Would it be harmful to the orchid to repot it while it is in bloom?
Thanks for your help,
Liza  

Answer
Hi Liza,

Thanks for getting back with more information.  

From your inspection and findings, it does sound like it might be caused by not being allowed to dry out enough between waterings.  Evergreen dendrobiums do not like going totally dry between waterings but it is perfectly okay to allow them to become barely moist, especially in winter.  

It is possible to repot while in bloom, it just takes a little more caution in handling so you do not break off or damage the blooms.  Also, dendrobiums love to have their roots confined so only use a slightly larger pot when you do repot it.  

Hope this helps.  

Jim Kawasaki
San Jose, Ca.