dendrobium kingianum and zygopetalum questions
 

Hi, I'm new to this forum. I hope I can get some answers to the following.

1. I got this dendrobium kingianum in June of this year. It started with a total of 4 leaves but has now lost them all. These are what the roots look like. Is this dendritic dead or alive ?

2. What is this growth on my zygo. Is it a new pseudo bulb ? Will a flower spike emerge from this ?

Thanks so much !

Typo
 

Not "dendritic", I meant "dendo "

The Den kingianum is very much alive. They do shed leaves under stress, or just when the canes are aging. Are there more roots in the medium? If not, you could repot it a little lower. They tend to do new growth in the spring, about the same time as they think about blooming. I have seen sprouts from Den. kingianum canes that look really dead - and yours are nice and green. For the Zygo, hard to say but it does look like a new growth - and spikes tend to emerge from new growths, even before the leaves and pseudobulbs fully develop. Orchids teach patience...but watching the process is both fun and a learning experience (lots of things to enjoy and get excited about even before the flowers appear)

Just for comparisn
 

The seller tossed in a smaller Dendro (also a kingianum)..
It's been growing quite vigorously while the other one has gone "dormant" ?

How should I take care of the leafless one ? (Watering, lighting, etc)

What is the reasoning behind potting it more shallow ?

Thanks !

roots
 

The roots that you see pictured are pretty much it. No more buried in the potting mix

The little leafless one has so many roots above the medium, I wonder if there are enough farther down to gather moisture. So I think it needs to be a little deeper, not more shallow - these grow naturally with roots largely exposed, but in environments where they get humidity and rain. So we use bark, etc. to provide a place to hold moisture, and also (more importantly) most air. The leafless one, other than perhaps potting it so the roots are covered, doesn't need any special care. This species is amazingly tough, thrives under a huge range of conditions. When the weather gets cold (and these can take temperatures down to near freezing) cut back on the water... they don't need a formal "dry rest" but when it's cold they grow slowly if at all (so don't need much water, or any fertilizer) and also don't dry out as fast. For both, you don't need to fertilize during the winter, start up again when you see growth. When you do fertilizer, do it gently (the conventional wisdom is "weakly weekly") - 1/4 to 1/2 of whatever it says on the bottle, less fertilizer more often mimics what they get in nature. For light, both like filtered sun. (Direct sun can burn leaves, but they do like it bright) You haven't said where you live... That's information we need to fine-tune the general advice.

roots
 

The roots on the leafless one are usually buried in the medium. I uprooted just to show what the roots look like. Normally I wouldn't uproot it, but it's very loose in the potting mix so it was easy for me to pull it out of the medium for the pic. Sorry for the confusion.

---------- Post added at 04:26 PM ---------- Previous post was at 04:23 PM ----------

The dendros are placed near a window facing SSW.

---------- Post added at 04:29 PM ---------- Previous post was at 04:26 PM ----------

I'm in the Northeast, so generally not too many extremes of temps for any long duration. Right now the humidity of the room that my orchids are 52/53 %. Temp is in the high 70's

The location should be fine... do you live in an area where these could grow outside? If you get cold winters, leave them in until danger of frost is past in the spring, then they will benefit from growing outdoors if you can do it. You will get lots of hypotheses about what trigger blooming such as a dry "rest" or cool nights. I suspect from my own experience that the latter is more important. So if you have to grow them indoors through the winter, place them fairly close to the window so that they get a chill.

---------- Post added at 01:36 PM ---------- Previous post was at 01:32 PM ----------

You answered my question about location while I was writing the answer... Humidity is fine. Once it gets cold and the heater sucks humidity out of the air you'll want to water more often to compensate. Once the weather turns cold, you'll get more of a chill close to the glass, and that should be sufficient.

The Zygo will be happy with less light, doesn't want to get cold, and needs more moisture. So you can put the Dens close to the window and the Zygo behind them (and do make sure that it gets water in the winter when the RH drops)

Winter rest
 

I was thinking about placing the dendros outside overnight once it gets to 50 or lower, and then bringing them back inside during the day. I'm slightly confused about what temps will trigger flowering. Is it an overnight temp of below 50 , or a consistent 50 or lower during the winter period ? As I mentioned above I will bring temp back indoors during the day where they will experience temps in the high 60's to low 70's. I don't want to leave the dendros outside because temps can get to freezing or belie in the winter.

If anything, I'd put the Dens out now, and let them experience the fall cool-down, bring in once night temps get down to the 45-50 deg F. range ... you don't want to be caught by surprise if a frost hits. These are young plants. As far as what temps induce flowering... you'll get lots of opinions but I don't think anybody knows definititively. (The Phalaenopsis growers have done a lot of research because it's their bread and butter to get predictable flowering, not particularly applicable to Australian Dendrobiums) I suspect it is more of a day-night and seasonal variation than an absolute temperature. I think the "close to the window" treatment will be sufficient. While both of the Dens are big enough to potentially bloom (even the little leafless one) the bigger and more robust they become the better the odds. To get reliable blooming, concentrate on growing healthy plants and they'll take care of the rest when they're ready. (My mantra is "Orchids teach patience")