Orchid Board - Most Complete Orchid Forum on the web ! - Water Quality and Dendrobium Cuthbertsonii

Orchid Board - Most Complete Orchid Forum on the web ! (http://www.orchidboard.com/community/)

- Beginner Discussion (http://www.orchidboard.com/community/beginner-discussion/)

- - Water Quality and Dendrobium Cuthbertsonii (http://www.orchidboard.com/community/beginner-discussion/72497-water-quality-dendrobium-cuthbertsonii.html)

Water Quality and Dendrobium Cuthbertsonii

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. :D

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!

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).

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.

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

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.

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!

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:

http://farm3.staticflickr.com/2835/1...9c22507481.jpg

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!

So how is it going?

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

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.

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.

I'm currently growing some tilandisia in my terrarium under a CFL. They are right at the top under the fixture and provide shade for the dracula, lepanthes and masdevallia below them. My oldest of the three is growing like gangbusters. I'm primarily concerned that my terrarium will be too warm. I have a dracula Lotax in there. It grows pretty well but these are more tolerant of warmer temps. I have seen the temp in my terrarium get up to 79 degrees, but a quick misting always brings it back down to 73.4 which is where it usually sits.

I'll be in the basement. Den. cuthbertsonii did very well in my previous setup there with temps occasionally popping up over 75 during the day (usually 70). However, it always got down to between 60 and 65 at night, which I think is important.

My house does get that cool in the winter, but not in the summer months. I woke up this morning to find my terrarium at 67 degrees. I may need to set up a second terrarium because I purchased a couple of plants without double checking their climate and I have some hot to warm species and they may need warmer conditions. I'm already in talks with a friend to purchase his exo-terra that's the next size up from mine. His boa outgrew it and he doesn't need it now.

I have one of these, the tag from Andy's says light from shade to bright. Right now I am trying it on slightly higher than phal light so I will try to up it. I have it on a Kool log but right away it was too much moisture maybe for this time of year or too much in general without drying out. I kept it on the log but I only wet the moss daily and do not fill the chamber. Seems to be working so far. The Andy's tag also says keep wet and cool, good water quality a must. I use distilled or rain water.

Mine sits just under the light less then an inch away. Many leaves are purple, which is fine The key is getting temp down to 50f at night and keep the roots always wet, but not the plant or bloom.

Attachment 117225

Sent from my LG-D855 using Tapatalk

I'd like to revive this thread. Anyone still growing these? I have 3 now and are all still alive. It seems like sometimes it's a fine line between too much moisture or too dry. They like it "just right" and I'm trying to get there. I have mine in a dab of s.moss surrounded by clay like pellets. 2 are sitting in a clay saucer while the 3rd is in a small plastic pot.

Yes, I still do and they are doing quite good. Here are pics of two that just recently started flowering.

Sent from my LG-D855 using Tapatalk

Ok, no photos accepted or whatever. I now have six different plants, all seem to be fine in an enclosed wine chiller at 22C day and 10C night. Daily watering with rain water.

Sent from my LG-D855 using Tapatalk

Thanks DavBis, do you fertilize, if so how often? What media are you using? Thanks in advance.

I do fertilize about every two weeks, but I do forget sometimes. I usually leave them as they arrive, but when I repot I use sphagnum.

Sent from my LG-D855 using Tapatalk

RandomGemini originated this thread with some questions. Among them were "What does water quality mean with respect to orchids?" It refers to how pure the water is and how acid the water is.

Minerals, mostly calcium and magnesium salts, are dissolved in ground water. Rain has few of these minerals, unless there was a lot of dust in the air. Minerals in water are commonly described with measurements called Total Dissolved Solids or TDS, hardness and alkalinity. Hard and/or alkaline water tends to have more calcium and magnesium in it. TDS does not measure which specific minerals are in the water, but it is almost always calcium and magnesium salts.

Epiphytic orchids tend to prefer water with low to very low TDS. Most of them are not adapted to water with higher salt content.

Ocean shore orchids, and a few from semi-desert areas, often can handle higher TDS in water, because they're adapted to being sprayed with salt water, or having alkaline and hard desert ground water.

Cloud forest orchids, and terrestrials from near streams, often need water even lower in TDS than some other orchids. Examples are many Pleurothallids, Paphs and Phrags. When watered with water high in TDS, these plants begin getting brown leaf tips, which spreads up the leaf until the leaf dries up and dies. This represents excessive salt accumulation in the leaves.

The other factor in water quality is the acidity of the water, measured in pH units. The pH scale runs from 1 to 14 and refers to solutions of things in water. You cannot measure the pH of a solid; only something dissolved in water. Lower numbers are more acid, and higher numbers more alkaline. Your stomach produces hydrochloric acid with a pH of 1. Lye, or sodium hydroxide, when dissolved in water, has a pH of around 14.

Pure water, with no carbon dioxide dissolved, has a pH of 7, and is considered neutral. Distilled water sitting on the shelf is slightly acid because of the atmospheric carbon dioxide dissolved in the water.

Most orchids (most plants in general) do best watered with a pH not too far from neutral. Well water, and most municipal water, has a relatively high pH, and is not always good for orchids. Fertilizer intended for use with tap water often brings the pH down and closer to neutral. Often the many dissolved minerals in water cause the pH to be high. There are plants with definite preferences for alkaline or acid water. Acid-loving plants tend to come from areas with a lot of humus on or in the soil, or in very wet, marshy areas. Alkaline-loving plants tend to come from deserts, like cacti and most succulents. Minerals don't wash away when rainfall is low.

The pH scale is logarithmic, meaning it does not increase at a constant rate: the difference in acidity from 2 to 3 pH units is not the same as the difference between 3 and 4 pH units.

The acidity of water increases 10 times when you move from one pH unit to the next lower number. Moving two pH units lower increases the acidity by a factor of 100. That is what is meant by a logarithmic scale. So, water with a pH of 6 contains 10 times the acid of water with a pH of 7, 100 times the acid of water with a pH of 8, and 1,000 times the acid of water with a pH of 9.

Dendrobium cuthbertsonii... I haven't grown it. But it seems to be a cloud forest orchid. This means it gets rain with very low total dissolved solids. Rain is normally slightly acidic due to dissolved carbon dioxide. It likely grows on patches of moss, which means it has an acid environment. So I would expect this plant to do poorly with most tap water, which is high in TDS and alkaline. Some municipalities have purer tap water, but this is not common.

You can read the water quality report for your tap water utility online. Here you will find the pH and mineral content of your tap water. If you are hoping to grow orchids with tap water, you need to be familiar with your tap water. I can't use my tap water for most of my orchids.

Thanks e.seca, good explanation. I am growing more in rain water. Most people think den cuthbertsonii are hard to grow. I think they require good water and also they need the right amount and when. My plants are very small. I think once they get a bit bigger I might feel a little less anxious. It seems like they like to stay moist but if they are too moist they drop leaves, it's finding the balance and giving the right environment.

Wow, fantastic! Can you tell me about watering, temps ect? Thanks in advance.

Thank you. I water mostly daily with rain water and fertilize now about once a month or even less often. Temps 22C daytime and 10C night time.

Sent from my SM-T230 using Tapatalk

One point that should be touched on is the indiscriminant use of the phrases "tap water" and "well water". My current tap water has a tds of 200. When I lived in NJ it was more like 50. A friend has a well. His tds is over 400ppm. My mother gets her water from a township well less than 5 miles away from my friend's, and her tds is around 300. A house I looked at in NH had well water between 20 and 30ppm. If you have municipal water, your supplier is legally obligated to provide the results of a very thorough analysis free of charge. If you have a private well you should have a lab analysis done, for your own sake let alone your plants. At the very least you can take a sample to any decent aquarium store and they can give pH, hardness, and alkalinity values. This is normally free. This is stuff everyone, not just plant growers should know.

My rain water is about 25ppm.

---------- Post added at 08:31 AM ---------- Previous post was at 08:06 AM ----------

Few months have passed and few more flowers have opened. Hope you will enjoy these photos.

Please use following link as photos are so difficult to upload. Dendrobium cuthbertsonii – Miniature Orchids