Dendrobium Nobile - Winter Rest?

[eevee94]

I purchased a Dendrobium Nobile (Clouds Snow Bunny) from Clouds Orchids Spring 2018 and at the time it was described as a large seedling.

I repotted it into semihydroponic, it seemed to enjoy it and grew a number of roots and it made 1 new growth and a keiki this summer. I started slowing down fertilizer around August, and stopped by September. I've been reducing watering (1 week, then 2 week, now 3 week or whenever it looks really dry) since late September / mid October.

I live in Toronto ON, and temperatures have been mild lately (-5 to 5 range) and I grow it on an southern exposure window. It seems happy. It now has about 5 nubs, and it is December 20. I'm not sure if they will be keikis or flowers, but I have my fingers crossed. It has not lost any leaves, but one leaf is yellowing. I do not see any bulb shrivelling either.

My Question:
1) should I continue Winter Rest (and if so, for how long?)
2) Or should I gradually reintroduce watering?
2A) When should I begin applying fertilizer?

Any help would be appreciated.
eevee94
(P.S. it's my first time posting on OrchidBoard, even though I'm always reading this site...)

[aliceinwl]

I'm not sure if being in semi-hydro changes things, but I try to follow the general timeline given in General Care for watering and fertilizing. I was a bit late on putting mine into rest last year, but it still bloomed.

[MrHappyRotter]

The name of your orchid is Dendrobium Cloud's Snow Bunny. It's a nobile-type hybrid, though I'm not sure about its warmth tolerance. Modern nobile hybrids tend to be a bit more forgiving (and more floriferous) even if the winter rest and cool conditions aren't quite optimal, but some can still be quite fussy about winter conditions.

I'm not sure how or if semi-hydro would affect things, but here's what I'd do.

1) should I continue Winter Rest (and if so, for how long?)

Sure. Continue cool, dry winter care. If the nubs turn out to be keikis, then I suppose at that point you can (slowly) transition from winter rest to standard growing conditions. If the nubs are flowers (or you can't tell) then continue with the cool winter rest. You have to let the plant be your guide, but it's not unreasonable to continue winter care well into February or March. The main thing is, the cooler your temperatures, the drier the conditions should be. Don't worry if additional leaves fall off. These are also referred to as deciduous Dendrobiums, though due to modern breeding and because of variations in care, they may or may not actually drop their leaves.

2) Or should I gradually reintroduce watering?

Yes, it should be a gradual process. If you see the nubbins turn out to be keikis, then you can resume watering. If you see new growths at the base of the canes, then you should definitely start watering again (especially if new roots are forming, too). If the canes start to shrivel, you can water a bit to help rehydrate them.

2A) When should I begin applying fertilizer?

When you see new growth, particularly new growth that's starting to produce roots. Again, you should let the plant be your guide, and it wouldn't be unusual for this to happen as late as April or May. If you're careful and start at low doses, you can start once the flowers are finished.

[estación seca]

The Yamamoto link aliceinwl posted is now gone. It said cool temperatures are more important for bud formation than water restriction. Also that keikii instead of bud formation is most commonly caused by fertilizing too late in the summer.

A lot of these are sold in flower in markets with full sets of leaves. The growers keep watering them.

Edit June 15 2020:
Yamamoto Dendrobiums in Japan hybridizes and produces a great number of these plants. Their Web site formerly had excellent growing information for hobbyists. Unfortunately it is no longer there. You can still look at the varieties they grow, and maybe see one very similar to yours.

I saved the page, and summarized it in a post in this thread:
Uncertain if Dendrobium is still alive

Yamamoto now has a page showing how to force Dendrobium nobile for Christmas flowering in Japan's climate. There is a lot to learn from that page, but it is intended for growers who can artificially heat and cool their greenhouses during off seasons. Note they use coconut husk for growing medium, which many orchidists would say retains too much water for orchids. For many orchids that is correct, but this is a very thirsty orchid.

[POLKA]

if you have been withholding water, and you have nubs, you most likely will have flower buds forming. Start watering when the nubs become obviously flower buds thru separation and short flower stems on each. If you are getting keikeis, start watering about a week after root nubs are obvious. When in doubt, WAIT. happy growing!! R