Dying dendrobrium? Leaves yellowing and dropping.

[Tpa Bay]

New orchid grower here. So far I'm having luck with a couple of phals, a Cattelya, and a Vanda but I'm concerned about the dendrobrium I bought. It's a New Guinea dendrobrium with no species name so I guess it's hybrid. I bought it at lowes in one of the plastic bags with just canes and leaves, no buds or stalks. I repotted into the same pot with mostly bark and a little moss, and at first I had the small pot sat into a larger decorative phal pot with the same media around it. I took it out of that a couple days ago.

I live in Florida so I have it outside on a south facing patio. It gets mostly bright but indirect light and only receives a couple of hours of direct sun. I was watering twice a week, but dropped back to once when the problems with the leaves started. I mist daily in the morning but our outdoor humidity is rarely below 50%.

The leaves on the largest cane are yellowing and dropping. I don't know if this is a deciduous plant. I thought this cane was about to bloom, but now it looks like it's dying. It started with the bottom leaf and went up, I cut the next two off, and now the top one is doing the same. Not sure if it's sunburn, over or underwater or just natural growth. Also considering reporting into an orchid pot with more drainage and aeration as it's currently in a cheap plastic pot with no side vents. Help!

[No-Pro-mwa]

Welcome to the board. I am also a new Den grower as I only have 3 of them and I haven't had them yet a year. So I can't tell you what kind you have but it could be just changing environment that is causing it. I would leave it alone and not re-pot it again none of mine have wholes on the sides of there pots. Only bottom wholes.

Water it when it is dry you might be letting it dry to much. But every place is different and 50% humidity is pretty good I would say. It gets so dry here that I have to water mine allot more than it seems most people do. Do you feed it?

[rbarata]

Don't know what you have but my nobile looses the leaves after flowering while new canes start to grow.

[Lady Meera]

I experienced something very similar with my first (and only) dendrobium phalaenopsis. I bought this before I knew I was supposed to keep the tags so I don't know for sure what kind mine is. I'm assuming it is a Den Phal which is not SUPPOSED to be deciduous. I've heard some Dens are semi-deciduous though.

Anyway, here is how it went down and how I 'solved' my problem.

1) I brought it home and put it outside and it got sunburn within minutes (yellow spots on some leaves)

2) then almost all the leaves starting turning all yellow so I thought it was getting too much sun in the house, even though the care sheets all said it liked full sun, so I moved it to a low light area of my house where it bloomed, though poorly (spotty flowers and only 3 blooms on one of the spikes)

3) I tried watering more (because care sheets said it doesn't like to dry out) and then watering less because the leaves were still yellowing and falling off.

4) all the while I was using a balanced fertilizer (20-20-20) because the care sheets said not to give high nitrogen because it will grow too much foliage and not bloom.

5) leaves still falling off

6) as a final straw, I repotted it in plastic (to increase moisture) and placed it in the highest light area of my house (in front of a large west-facing window). I also switched to a high nitrogen fertilizer (30-10-10) since it wasn't doing anything except dropping leaves.

7) It is still slowing losing leaves on the older/smaller canes but the largest/newest cane looks great and it is growing a new cane!

I have read and am thinking that the older canes can lose their leaves, especially if the plant is not in ideal conditions. However, you are supposed to leaves these old canes on the plant because they hold water for the plant.

I suggest just giving your plant it what it needs and not worrying about the leaves falling off as long as the roots and the canes look healthy.

The pictures show the progression of my poor plant. Hopefully they show up in order. If not, I have them numbered sequentially in the file name. If you look closely at the first one, you can see the sunburn on the right side of the plant. It looks like yellow spots. The other leaves that fell off the whole leaf turned yellow from the tip on and dried out. I'm not an expert, but if your plant used to live inside the store and then you put it outside (like I did) it is possible that it could have gotten sunburn. Mine was only out there in direct sun for a few minutes.

Good luck!

[gngrhill]

I have also always had issues with leaf loss in my Den/Phals. I was just talking with Brenda at Black Meadow Flora this weekend at their open house, and told her the problems I was having. She and Margaret both thought it might be too much humidity and too much watering. They thought that 50% is a good goal for humidity. I have since cut back on my humidity and am also going to let them dry out more between watering and see where that gets me. I hope this helps.

[estación seca]

Your plant actually looks pretty good. Did the yellowing leaves fall off the oldest pseudobulbs? This could easily happen on a plant that's spent some time in a store in less-than-ideal conditions.

New Guinea Dens and Den phals need different care to thrive. Both should do very well for you with proper watering and light. Did your plant have any kind of label? I'm guessing it might have, because most new orchidists would not know what a New Guinea Den is, and your plant indeed could be one.

If it is a New Guinea Den, it might keep making new pseudobulbs most of the year. It should not dry out completely. Some people water and fertilize them throughout the year; others stop fertilizing in the winter, and cut back a little on the winter water.

Den phals should dry out completely between waterings all year, and they should be dry for a few days in the winter before watering again. Most people don't fertilize them in the winter.

Neither of these Dens likes cold temperatures. Both should get as much light as possible, short of burning the leaves. Your plant has been indoors for a while, so move it gradually from shade into more sun. When the leaves start getting a little yellowish, that is too much.

[wintergirl]

I have a lot of den species. The hybrid den phals are more touchy. They will loose leaves when you look sideways at them. The only thing they I have found is a clay pot and chunky bark. Then I just squirt a small bit of water near the plant only. And I mean a small amount. I do this everyday. I never really dunk or fully wet. When I do, I loose leaves. This is what is working for me. Also I have in a North window, slightly back and no added light.
Right now this is the only way I can keep it happy.

[Fairorchids]

Orig photo seems to show a Den phalaenopsis type.

I grow mine in clay pots with bark/spaghnum mix. We water heavily twice a week in summer, and once a week in winter. We fertilize every two week, except Dec-Feb (once a month).

We recently had a heater problem (failure), leading to a couple of very cold nights in the greenhouse. That caused some yellowing & dropping of older leaves.

[wintergirl]

Originally Posted by gngrhill

I have also always had issues with leaf loss in my Den/Phals. I was just talking with Brenda at Black Meadow Flora this weekend at their open house, and told her the problems I was having. She and Margaret both thought it might be too much humidity and too much watering. They thought that 50% is a good goal for humidity. I have since cut back on my humidity and am also going to let them dry out more between watering and see where that gets me. I hope this helps.

I try to keep my room at 50% too.

[Leafmite]

Years ago, it was often advised to mount these and water like crazy. :| However, I find these very easy to grow in large chunks of red lava rock and a basket or clay pot. When watering, I soak it for a few minutes to give the roots time to absorb water. One of the advantages is that that there is no need to again disturb the roots and, after a year or two, depending on the hybrid, it might be in bloom nearly year-round. Another advantage is that when it is laden with spikes of flowers, it isn't easily knocked over because of the weight of the rock (unless you have kids....).

The reason that it is nice to avoid re-potting these is that, if your growing conditions are not perfect (like Hawaii), some of the Phal-type Dens. might sulk when the roots are disturbed.
Good luck!