Dendrobium phalaenopsis care?

[aliceinwl]

I just got what looks to be some type of Dendrobium phalaenopsis hybid. It's in moss right now. Are there any good care sheets out there? I'm assuming it can eventually go into bark, but I was wondering when would be the best time to repot it, how wet should I keep it, and what is it's lower limit in terms of temperature? I've seen 60 degrees listed on some websites for Dendrobium phalaenopsis, but I've seen that for other orchids too that actually can go a lot lower. I had to bring most of my phals inside this winter, but I have two phals that are still outside because they've kept growing and blooming despite regular night time lows in the 40s.

[No-Pro-mwa]

I don't have any of these but I have read that you don't re-pot Den. until spring when new roots start. However it would not seem to me that sphagnum moss would be a very good medium for them. I would defiantly let it get to the dry side before watering again. Hopefully someone with more experience with them will show up soon.

[estación seca]

Repot when new roots are forming. This is usually on new growth emerging from the base. It probably won't happen until temperatures warm for you.

Dendrobium phalaenopsis plants are easy to grow if you give them what they need. They grow very fast and make huge amounts of flowers under the proper conditions. Unfortunately, what they need is a little different from what most people have in their homes through the year, so adjustments need to be made.

The warmer you can keep Den phal hybrids in winter the better for them. 60 F / 15.5C is about as low as I would go, and only if they got a lot warmer the next day. I have seen 40 F / 5C kill them. They would really prefer Honolulu or Durban or Taipei or Singapore weather all year.

Some species in their background come from areas with completely dry winters, but hybrids are better watered all year.

When pushing new growth, they must not dry out. If they do, the new growth will be stunted, or even die. If this happens more than once the plant may die.

Leaf drop on pseudobulbs less than 2 years old is not normal. It is usually caused by insufficient watering, or temperatures too low.

They need air at the roots. Hawaiian growers often pot them in large bark, in small pots. This is because it rains so much there. Windowsill growers can have trouble keeping up with the watering of a Den phal in large bark in a small pot. I am having much better results since switching mine to large pots and medium bark. If I had fine bark I would have used that. Note I have lower humidity and warmer temperatures than many people, and fine bark in a large pot might not work for others.

They prefer high humidity, but this is the least important factor in their care. They will grow and bloom in typical household humidity. This is because some species used in hybridizing experience a months-long dry spell in winter, with very low humidity and no dew.

If you know how to grow in sphagnum, it might work for you. Only water to the point of being sopping wet during hot weather, when the plant is pushing new growth. Under these conditions the plant will use the water quickly, and the sphagnum will soon open up, to allow air to the roots. During other parts of the year, you should only water enough to lightly dampen the sphagnum. This preserves the air flow through the sphagnum.

[aliceinwl]

Thanks for the run down! It sounds like this one will have to stay indoors. It’s in full bloom now and about 2 feet tall (not counting the flowers) in a 4x4 inch pot. Based on your advice, I’ll try to baby it in the spagnum it’s in now (it sounds like moisture levels in the moss should be similar to a paph?) and then repot into bark and a bigger pot once I see growth. Do you think I could get away with moving the whole plant now, moss and all, into a similarly sized clear pot for ease of gauging when to water?

[estación seca]

I wouldn't move it now. Hold the plant in your hand and notice the weight. It will become lighter as the moss dries.

[aliceinwl]

My Den. phal. finished blooming last month and I moved it outside. So far (about a month now) it’s been taking the temperatures fine with lows in the high 40s and highs in the mid 70s. It’s also started pushing new growth and roots so I want to repot.

I pulled it out of the pot to check the roots today and the moss is actually just a top dressing to some really old looking bark. Can these tolerate overpotting or should I keep it small/tight? I’m also trying to decide between a clear plastic slotted pot and terra cotta. The clay would have the advantage of weight to counteract top heaviness but I wouldn’t be able to see the roots.

[estación seca]

Both types of pots work well. If you tend to underwater, use a larger pot. My impression is most of these die from underwatering, but some people tend to overwater. Cattleyas often seem to do better in pots drying out between watering, but not Den. phal hybrids during the growing season.

[Dollythehun]

Keep your pot heavy and low, especially if it's outside and the wind could catch it. These are top heavy. Repot when you see new roots. I water 2-3x a week but your climate is different. I'd also put it in medium to small bark. I don't put my Den phals in moss...or any dens for that matter.

I also would never leave them that cold at night but it's working for you. It would be colder and wetter for them in moss and that might be problematic.

[Roberta]

With weather warming up, it should be fine outside until fall, and will benefit from the light (which it needs lots of) and air movement. Night lows are only for a few hours. If there are signs of new growth, now is a good time to pot. Terracotta pots are good, especially for the weight. Most Dens have rather small root balls relative to the size of the plant, so a bit of under-potting is recommended - go by the size of the roots, not of the plant.

[aliceinwl]

I re-potted before I saw Roberta's response. I decided to go with a larger pot thinking that this might fit better with a weekly watering regime and help it weather the periods when I'm out of town and it might have to go a bit longer. I also rigged the pot so that it's hanging. I probably went about triple the size indicated by the root ball. I don't think it would be hugely traumatic to re-repot it.

Can these take direct sun? I have it hanging on an eastern fence that's partially shaded by an olive tree so I can move it from no direct sunlight to morning through afternoon sun. Right now it's in shade, but I was planning to gradually move it into more light.

I have my Dendrobium nobilis types in the sunniest spot, my Maxillariella tenuifolia and Laelia aniceps in a spot that gets a bit less sun, then my Oncidium flexuosum in an area that just gets a couple hours of sun in the morning, and my Den Roy Tokunaga and Den Little Atro in shade. The latter two Dendrobiums were getting some leaf burn when I had them positioned with the Oncidium.