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

tinctus · #1 05-19-2011, 06:32 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.

King_of_orchid_growing:) · #2 05-19-2011, 07:44 PM

The grower's advice is extremely sparse and way too general.

Dendrobium victoria-reginae can handle temperatures much lower than the ones you mentioned. They can handle it down into the 50's F, maybe even lower (I wouldn't go any lower than 45 F, maybe 36 F).

It is also semi-deciduous. Which means, it does naturally drop older leaves, but still retains newer leaves. Eventually, the oldest canes will drop all its leaves.

Since it's being grown in a wood slat basket, the frequent misting probably isn't really hurting it. The real key is to see how the roots are doing.

Den. victoria-reginae tends to naturally have a sprawling habit, where the canes just radiate in every which way.

The growing media might be fine. Check the roots.

Here's a link to some info on them:

IOSPE PHOTOS

You might want to get a light meter for the light measurements. Your pics would suggest it's getting enough light. But then, you put up a numerical value in footcandles that seems to challenge that it is getting enough light. It's better to check for certain with a meter, in this case.

Btw, flowers are not the best indicators of health - even for Dendrobiums.

WhiteRabbit · #3 05-19-2011, 11:49 PM

hello! welcome!

mine grows outdoors, year round (zone 9) - unless the overnight low is forecast to be near freezing or lower

these don't want to dry out - maybe try a skewer in the media to monitor the moisture

probably the plant could use more light - when grown on windowsills, plants usually need to be quite close to the window to get sufficient light - skylight is probably too far away, and not clear glass, and so probably very low light reaching the plant

gl

Zoi2 · #4 05-20-2011, 12:29 AM

Hello and welcome to the OB.
I'm not a den expert of any kind but I do believe your light levels are way low. I would think the minimum level would be around 1500fc.
When you water every 3-5 days are you actually soaking this plant or just misting it? If you're misting only I wonder if it's getting enough water.
Joann