Water Quality and Dendrobium Cuthbertsonii

[RandomGemini]

I would like to preface this by saying, I have learned that dendrobium cuthbertsonii is NOT a good orchid for beginners... and yet, here I am with one and I'm new to orchid growing. So, this seemed like the place to post it, but I could be wrong and will not feel any sort of negativity toward anyone who thinks this thread belongs elsewhere. I would also like to blame kindrag23 for this thread. We started talking about this orchid on another thread, and now I have doubts, so I am gonna ask.

I've had my dendrobium cuthbertsonii for about two weeks. I feel lucky that I have seen a new leaf open up in this time but I suspect this has nothing to do with my care and more to do with the care of the orchid grower I purchased it from. Still, I find myself quite pleased that it's not sulking, so I'm calling that a win, for now.

I'm growing it indoors in my home office, so I can't grow it mounted, it will dry out too fast. I'm keeping it potted and watering it every other day by spraying the moss in the pot down with bottled water until it's just a bit past damp, then I leave it to dry out until the top of the moss gets a little bit crispy.

I know my tap is WAY worse than the bottled water I've purchased. The TDS on the bottled water is less than 100. I'm waiting for new RO cartridges to come in, then I can water it with RO.

I have a humidifier and a fan going in there, pretty much 24/7. If the humidifier is running low when I walk by before bed, I shut it off and refill it in the morning. I have the little guy's pot sitting with my dracula lotax (which is growing like a weed in this location, new roots all over the place, I'm loving it!) for the time being, about a foot or so away from the east facing window in that room.

Does everything I'm doing sound good so far?

I've been reading about this species until my eyes feel like they are going to fall out. Some growers say that this needs more light than I'm giving it. Others suggest that it would be best if I grew it in a dark closet, but I'm not about to do that. The leaves on my plant have remained tinged with purple, just as they were when I purchased it... and I believe this is a good thing for this species, if I'm reading all of the material correctly, so I'm staying with that if it's an indicator that I'm doing anything right.

I know that all of the guides say that dendrobium cuthbertsonii needs "pure" water but what I want to know is, what the heck does that mean?

I know my tap water isn't pure. My dogs have a recirculating drinking fountain with filtered water running through it. That's how little I trust the tap water. That said, my phals and oncidiums receive tap water and they seem pretty happy with this arrangement. My dracula, bulbo and the dendrobium cuthbertsonii, get bottled water. I think I may start giving the bulbo tap water though if it doesn't perk up in the next two weeks. It doesn't seem to be thriving the way the dracula is.

I'm assuming that "pure" means fluoride and chlorine free water, for sure, but is there anything else I need to worry about here? Are there certain minerals that cause this species to sulk? Does it mean using rain water? I can certainly start working on that once it snows, but I don't think it will really rain again before about December when it starts snowing so that might not be good enough for me. I worry that we won't get enough rain for me to be able to water this orchid with rain water and nothing else. It pretty much doesn't rain from about June until September here.

I can give it distilled water, but how will it get the nutrients it needs that way? I've been told by a local orchid grower that fertilizing it is how she killed several of these. So not fertilizing it sounds like good advice to me, because I'm new to using liquid fertilizers anyway. But, I want to make sure it gets some nutrients somehow.

I think you can see why I'm struggling.

There's an OS meeting here next month on the issue of local water quality and orchids, but it helps me understand a subject better, if I get feedback from a lot of different sources. I would love to hear the thoughts of some folks who have experience growing this species.

Sorry for the novel and I thank you for taking the time to read it and help me out!

[ronaldhanko]

I grow these very well and for me the solution to all the problems was very high light. I am convinced that they are more temperature tolerant and will not be hurt by water or fertilizer when grown under high light. I use tap water on them and fertilize them several times a week with a weak solution of K-lite and they are thriving. One plant has a dozen flowers and all of them are blooming right now (a dozen or more plants).

[RandomGemini]

Are we talking about cattelya light?

I know that with SPS corals, they tend to be more disease resistant and thrive better in home aquariums if you can throw as much light at them as possible. The more zooxanthellae on a coral's skin, the healthier the animal is going to be, so generally speaking, the brighter the better. So, it makes sense that providing higher light would make the plant more resilient.

I could set up a terrarium for this orchid. I have a good chunk of the equipment I need, but I'm not sure about the bulbs I have in the fixture I would use. I'd have to do some research on artificial lighting for plants. I've done a LOT of reading on how one does it for corals, but I've never grown plants this way. I've always used plain old sunshine. The 13" lighting setup I have, has a 25w bulb with one daylight and one actinic tube, for growing gorgonians, mushroom corals and zooanthids.

[bethmarie]

Thanks for this thread, Gemini. I've got cuthbertsonii & a couple of its primary hybrids and I'm always interested in learning more about them

[ronaldhanko]

I am growing mine under a bank of eight HO T5 48" lights and some of them within inches of the lights. I have no light meter but that is certainly enough light to grow Cattleyas (I've grown and flowered minicatts under less light) and they are doing better than I have ever done with them.

[RandomGemini]

That's a lot of light, probably a lot more light than I can provide at the moment, just because I don't have the space. I'll have to see what's out there. Lighting has changed a lot since I researched it last, I might be able to find smaller, more energy efficient setups than were available to me ten years ago.

I'll post some updates when I come up with a plan.

Thanks for the food for thought, Ron!

[RandomGemini]

I've just about got a plan for how I am going to do a terrarium for this little orchid and I hope to be able to set this up by next weekend. I checked on it this morning, like I do every morning and I found this:



It's so tiny that I'm not sure if that's a new leaf, or a cane growing, but I'm pleased with ANY new growth at all. And then... I saw the red leaf and another leaf that looked quite pale.

Not enough light? (Working on that! Hoping to have a terrarium set up by next week!) Water quality issue? (I can fix that! I'll switch to distilled water for a few days while my RO unit primes.)

I don't want to kill the little thing already!

[Duane McDowell]

I'm curious to hear how your little Den. cuthbertsonii is doing now.

[RandomGemini]

I killed it. I'm considering trying it again at some point in future once I'm sure of my terrarium's environment. I just couldn't keep it wet enough without one.

[Duane McDowell]

My experience with these is that they need a ton of light (Cattleya+). I did mine with CFLs a few years ago. I'll be setting some up with LEDs now.