Orchids/Dendrobium yellowing and browning from tips
I have a problem with a dendrobium I received last fall. After blooming, a new cane emerged and grew. However, for a while now the new growth has started to die back. It started on the leaves in the middle; the tips would yellow, spreading to the cane. The tips would brown and follow the yellow as it spread. Now it is starting with the top of the new growth as the new growth has seemed to slowed down almost completely. The whole cane was bright green, but now seems to have taken a yellow tinge to it. I made up a dilute solution of acid-loving-plant fertilizer a month ago to see if it was a deficiency, but nothing has changed. I always wait to water the plant when the media is completely dry. It's in pure sphagnum with some orchid bark.
Do you know any reasons for this dead new growth?
Dendrobiums can be tricky to grow. Some are deciduous. This type lose some or all of their leaves after completing a growth cycle. When deciduous dendrobiums are watered out of season (ie during their rest period) they can begin new growth, which is inevitably weak.
Following new growth, dendrobiums should be given a rest (which can last for several months)during which they receive little to no watering and no fertilizer. Following rest, dendrobiums will naturally begin new growth. When new growth begins you can begin watering and feeding to support the new growth. If you water during the rest period, not only will the new growth be weak, but it is possible to rot the plant.