Dendrobium (victoriae-reginae) - Yellowing leaves - Orchid Board

tinctus · #1 05-19-2011, 05:32 PM

Hello everyone!

First off, I've been a long time lurker only to create an account today. For almost two years I have been dealing with orchids (mainly supermarket phalaenopsis) with some success. Ive successfully converted (a year+ ago) a phalaenopsis and a maxillaria (both unknown ID's) to semi hydroponics with the info already on this board. They haven't bloomed yet, but I've had significant new growth. Thanks for that!

Anyway, to the reason for this post. Early this May, my friend bought me my first real orchid for my birthday from a real-deal orchid grower. I tried to convince her to hold off until I am a little more comfortable with my orchid growing skills. Anyway, we came home with a beautiful Dendrobium (victoriae-reginae) with brilliant purple blooms. We were on a tight schedule, so I didn't have too much time to pick the growers brain about care for the plant. To sum up the info he gave was that this orchid likes to be watered often, enjoys misting, wants a temperature around 70°F, and should be kept out of direct sunlight always. The plant was positioned near a corner of his greenhouse, which was in partial shade but not underneath anything.

This plant was purchased in Rochester NY early May, a week later traveled 400 miles home with me to Virginia. During that week it lived in my friends apartment where I kept it out of direct sun, misted it quite often and watered it twice, unfortunately with tap water. The day it came home to Virginia, one leaf had

Now the dendrobium lives in my bathroom (68°F-75°F with about 50-60% humidity and some airflow) underneath a west-facing skylight. The sun never makes direct contact with anything other than the walls of this skylight (see attached current enviornment.jpg, heavy overcast day, it wasn't that bright), so I am assuming that is good enough light levels for it. As for water, normally we use filtered well water that is treated with potassium chloride. Practically everything in&out of the house is watered with this water, including my semi-hydro orchids. I do flush them fairly often to remove any buildups. Today I made the switch to collected rain water. Watering generally takes place about every 3-5 days, as from my research they like lots of well drained water when blooming, and the potting medium currently drains extremely quickly. I tend not to flood the plant when watering also. I believe it is a bark mix with some sphagnum moss on the outside. I mist daily before noon.

My main concern is the discoloring of the upper cane leaves (current bad leaves.jpg). They are different in appearance, texture and color to the other green and yellow(ing) leaves... they are alot floppier.

Another concern is the yellowing of the lower cane leaves (current plant.jpg). My guess is the yellowing is due to environment change, though it appears to be happening to all of the leaves on every cane, save for the one with the most leaves on the bottom left of (current plant.jpg).

So what do guys think is going on with the leaves? Over-watering? Wrong water? Environment change? Wrong light levels? I don't think its normal, cause the plant is still growing new buds and one of them opened just this morning. when I bought it this bud was quite small.

Sorry if this was long winded, but I wanted to give as much information as possible. Also, if the internet's math is right, the light hitting my orchid today on complete overcast around 2PM was around 334 foot candles, though that seems very dim.