First winter with Dendrobiums

[shakkai]

Since I added a few Dendrobium species to my ever growing habit, I am now more curious about the 'winter rest period' that these require. I was expecting to see them stop growing and start to show signs of wanting a 'rest' - however several have continued to put on new growth.

The ones I still see growing are: jacobsonii, brymeriana and unicum.

Do people 'force' a rest period by stopping/greatly reducing watering? The jacobsonii and brymeriana are on my (unheated) side porch where the temperature hasn't gone above 60F, so I would have thought it was cold enough for them to want to go dormant.

I had thought that I could 'take my lead from the plants' and decrease watering when growth slowed/stopped, but there is no sign of that yet and its getting late in the year....

What do you all do? Suggestions?

[Becca]

Great question! I am curious about the answer! I have a nobile type dendrobium in s/h and it is putting out a new growth too. Obviously I can't provide a winter rest with water, but I have stopped fertilizing it as of a couple of weeks ago...and then the new growth popped out? I also have the phal type dendrobiums (I hope that is the correct term) and they are putting out new growth as well and is in spike. But as far as I know the phal type dendrobiums don't need a winter rest, or so I thought.

[quiltergal]

From Jay's website..

Den. brymerianum: This species flourishes if left to dry out just a little between winter waterings but morning mistings may be nessasary, increase water and fertilizer with the advent of new growth. So, no true winter rest, just slightly drier.

Den. jacobsonii: A winter reduction of water and fertilizer is beneficial until new growth arrives in the spring. Again, not a true winter rest.

Den. unicum: A lessening of water and fertilizer is beneficial through the onset of winter but in the last 2 months water should be reduced even more and fertilizer eliminated until new growths arise in the spring. So gradually more severe reduction in water and fert towards the end of winter.

Becca, I put my nobile out in my sewing studio the end of October. The temps out their rarely get above 50F and I haven't been watering at all. One cane has dropped all two of it's leaves. I'll start watering and fertilizing again once I see flower buds. I think yours might be too warm? That's what prompted the new growth.

Hope this helps.

[shakkai]

Thanks, Terri! So, even though they are still putting on new growth now, I should start letting them dry out? I started to do that at the beginning of November, however, the brymerianum then had crinkled leaves on one of the growths, so I chickened out and started to water it normally again.

I guess I was confused because these descriptions make it sound like they stop growing, then resume growth when the temps get warmer/days get longer. However mine haven't stopped growing...

[Becca]

Originally Posted by quiltergal

From Jay's website..

Den. brymerianum: This species flourishes if left to dry out just a little between winter waterings but morning mistings may be nessasary, increase water and fertilizer with the advent of new growth. So, no true winter rest, just slightly drier.

Den. jacobsonii: A winter reduction of water and fertilizer is beneficial until new growth arrives in the spring. Again, not a true winter rest.

Den. unicum: A lessening of water and fertilizer is beneficial through the onset of winter but in the last 2 months water should be reduced even more and fertilizer eliminated until new growths arise in the spring. So gradually more severe reduction in water and fert towards the end of winter.

Becca, I put my nobile out in my sewing studio the end of October. The temps out their rarely get above 50F and I haven't been watering at all. One cane has dropped all two of it's leaves. I'll start watering and fertilizing again once I see flower buds. I think yours might be too warm? That's what prompted the new growth.

Hope this helps.

I think you are correct! I can't seem to get my temps down below the upper 60's degree's F., but I would have to double check that number on my memory setting on my temperature/humidity reader. The problem is that it is in s/h....and I am affraid that if I take it out of it's humid environment, that it will cause the conditions in the s/h culture to change and cause root rot, as I have discussed with Ray (low humidity causes quicker evaporation of the water through the medium keeping the roots cooler then needed, thus causing root rot, if I understood correctly), so I am affraid to take it out of the orchidaiurm, although I do have other orchids, mostly cimbidiums and oncidium alliances that have never been in the orchidarium....it took a lot longer for them to adjust to the s/h as well. Maybe I will look into bringing it out of the orchidarium for the winter, but continue with the watering, but not fertilizer since it is in the s/h medium. I thought Ray mentioned once, and I could be wrong, that he has experienced no winter rest with water needed with s/h with the nobile type, but I could be completely smoking it

Here is a link I found: Nobile dens...again

[quiltergal]

Shakkai, my interpretation for the brymerianum would be to go just a few days longer between waterings, nothing drastic.

[shakkai]

Cool! Thanks again! Very much!! I'm still getting to grips with these Dens. :-) But they are SO cool, I wouldn't trade them for anything.

[quiltergal]

Originally Posted by shakkai

I'm still getting to grips with these Dens. :-) But they are SO cool, I wouldn't trade them for anything.

That makes two of us!

[Ross]

I don't have any of these three but I do grow anosmum and it is a deciduous Dendrobium. I cut off water/fertilizer end of October and one (mounted on bark) is totally leafless now, other on tree fern (which seems to hold a bit more moisture) is about half without leaves. I start full water/fertilizer as soon as the buds are fully developed (like about 1 cm length) and new green growth is appearing. I don't do it slowly at all and there have not been any ill affects so far. This above regime would be for those that need total, drop their leaves, dormancy. Don't know anything about the others.

[shakkai]

Thanks, Ross. Can you say from what you've seen with you anosmum that the plant had matured its new growth and had stopped growing before you stopped watering?