Nobile Dendrobium Culture

[Bolero]

Hi everyone,

For those who subscribe, can I get you to have a look at page 574 of the October 2009 issue of Orchids Magazine and have a read of the first question asked. I have to say I was blown away and need to give more thought to their requirements. I will summarise as best I can:

It basically says that Keiki formation may not be the direct result of watering or fertilising too much during the rest period. It may be caused by temperatures that are low enough to activate 'lateral buds' but the low temps re not kept long enough and in the meantime the plants also experience warm conditions as well. Under these conditions high ferilisation may aggravate keiki growth. Studies have been done on this scenario which proves this theory is likely to be the case.

In order to trigger better flowering the key is to give the plants more time at low temps which should reduce keiki production.

I think this is major information, especially for me who has been just keeping them bone dry all winter.

What do you think?

Darren

[rcb]

Bolero - I read it as well. He uses the word may, which indicates the studies are probably still ongoing.

For my species Dens, there are some that require a warm dry rest, no matter his advice, I think I'll still keep them on the warmer side.

[berniep]

G'Day Darren

I'm not quite sure how to interpret that information.
I can only state how I grew mine (and I doubt anyone can say I didn't have a bumper show)

They were kept on a front verandah under cover (roof only) in the open air. Exposed to full afternoon sun.
No water or fert. from 25th April to 10th September.
I had no keikis except for the ones that were there when I inherited the plants.
The only thing I will change next year is to make sure the afternoon direct sun shines on the full cane not just the top section as the bottom was shaded by some shrubs, which stopped the bottom 6 inches or so not having blooms.

Cheers
Bernie

[Bolero]

I've been growing them for a while and growing them dry has usually worked although I have had periods when it hasn't and I've ended up with keiki's even with no fertiliser or watering during the drier period.

It's an interesting discussion and I thought there may be merit in this study, I guess there will be more information to come.

[kmarch]

I haven't yet read my issue. I'll have to get to it. I'm intrigued.

[syndywindy]

I read the article also and found it pretty interesting.

Originally Posted by berniep

G'Day Darren


They were kept on a front verandah under cover (roof only) in the open air. Exposed to full afternoon sun.
No water or fert. from 25th April to 10th September.

Cheers
Bernie

Can't argue with your sucess. I know you need to withold water during the rest period, but I didn't realize you can actually withhold water for 4 months and still have the plant survive that. So I guess I am asking how long others withhold watering their dens during it's rest period.

[Bolero]

Originally Posted by syndywindy

I read the article also and found it pretty interesting.


Can't argue with your sucess. I know you need to withold water during the rest period, but I didn't realize you can actually withhold water for 4 months and still have the plant survive that. So I guess I am asking how long others withhold watering their dens during it's rest period.

I would withhold water from late April until early October so just over 5 months or so. I do mist occasionally but maybe I withhold for too long.

[vcuchick]

I'm a novice Den grower- Anyone grow yours in S/H? by "dry" period...how dry is dry? No water at all? once every week or so? Sometimes these culture sheets are just too vague.

[Bolero]

With Nobile hybrids it means no water at all. But with S/H it might be different.

[tansyflower]

I still water once a week over winter. I do withhold fert for the winter months, but I do this with all my plants.

Different people have different advice. I have heard that giving a high nitrogen fertiliser will encourage keiki growth. This was from an orchid grower that sells fantastic nobile type dens at the markets.

[mgfree]

Originally Posted by Bolero

It basically says that Keiki formation may not be the direct result of watering or fertilising too much during the rest period. It may be caused by temperatures that are low enough to activate 'lateral buds' but the low temps re not kept long enough and in the meantime the plants also experience warm conditions as well. Under these conditions high ferilisation may aggravate keiki growth. Studies have been done on this scenario which proves this theory is likely to be the case.

In order to trigger better flowering the key is to give the plants more time at low temps which should reduce keiki production.

What do you think?

I had mixed results with my nobile types this year, maybe in part due to not having low enough temperatures this winter.

My species nobile was probably watered twice in the space of 4 months. The lowest temp we recorded for winter was something like 12.5 oc, but the minimum temp generally hovered up around 18oc this year. I didn't fertilise it at all & it got full afternoon sun from 2:30pm onwards. It formed what I hoped was buds, but have since turned out to be keikis (4 in total).

My other nobile type hangs out in full sun from say around 11:30am onwards year round. It only got watered when it rained, which was probably twice in 4 months. No fertiliser and it flowered (8 blooms only)

The previous year the same plant flowered, but also threw a few keikis in autum.

[berniep]

G'Day

Can't comment on s/h growing at all, but yes the plants are not watered at all for the four months. I was hesitant myself, but was determined to follow instructions to the tee.
The only other thing is it gets down to about 3 deg C here so there is a fair range of daily temps between low and high up to about 18 deg C.

Cheers
Bernie

[kmarch]

Originally Posted by Bolero

I would withhold water from late April until early October so just over 5 months or so. I do mist occasionally but maybe I withhold for too long.

That would be April through October in the Southern Hemisphere where these months are winter. In the Northern Hemisphere this would roughly translate to late October through early April. The dry period coincides with the cold period: cool, dry rest.

[11Orchid126]

Nobiles in the wild during their dry rest period experience very high humidity, especially at night. Misting the canes might be a better option than watering.

[zuri]

Thanks for this thread. I've got a nobile dendrobium that kept throwing what looked like up-and-coming blooms along its cane, only to have them shrivel and die after about a week or two. This happened three times through the summer. Something wasn't right.

Should the rest period, in addition to cool and dry, also be dark? Do I start the rest period now, or after it drops its leaves?

[Rivka]

yeah i have been wondering if the timing of when to start the dry rest is determined by the dropping of leaves? mine is starting to drop in ernest, so i have been assuming that i am soon going to let my s/h go dry.
yeah i was also wondering about misting, seeing how dry winter in home air is, i assumed that i would mist semi regularly. how do folks feel about that?

[jerrymeola]

I have not read the article but can comment from experience. I raise about a 1000 Nobile hybrids each year.

These plants take much more water than this orchid forum describes.

Mine get water every day until December and once a week after that. Fertilizer is a slow release type once a year in April. I am getting my best crop ever this year with an average of 2-5 new canes on each plant. I have flowered plants in the past with temperatures never going under 65 although I find 50 produces flowers on more plants.

I find keiki to be genetic. Certain hybrids will produce many regardless of what you do and most of mine will not. Den Red Emperor from Yamamoto is an example of one that produces many keiki.

Hybrids I have bought from other growers produce more keiki than flowers.

I do recommend the elimination of Nitrogen fertilizer in the winter, but have found when fertilized by accident it did not produce any terrible results.

I think the elimination of water in the winter is a terrible mistake. It prevents the plant from developing to its full potential.

Here is a photo of a species Dendrobium nobile that is grown in a Vanda house watered every day and then grown dry (once a week heavy watering) during the winter. The term 'dry rest' is relative. Nobile may handle total dry periods but it is not best.

This plant is in a 6 inch basket. It is 5 feet tall and has about 2000 flowers. It could not sustain that many flowers without water.

[kmarch]

Originally Posted by jerrymeola

Here is a photo of a species Dendrobium nobile...

Jerry, the orchid you have pictured is not the species Dendrobium nobile.

I corrected you the last time you posted this picture and incorrectly called it Dendrobium nobile (see posts #10 & 11 in this thread:http://www.orchidgeeks.com/forum/orc...t-keiki-s.html). Perhaps you missed that post.

[Bolero]

I wonder what that monster is!

I posted this as I love to grow them but I don't have many as I'm trying to figure out the right culture. THis article threw me a curve ball so I might experiment differently next year.

Thanks for everyones contributions.

[tansyflower]

I think it may be a Den pierardii (??). They also flower from leafless canes.

[11Orchid126]

Nobiles need a dry, cool, SUNNY rest. As much sun as you can give them, as much as for a cattleya.

[kmarch]

Yes, tansy, that's another good possibility.

As it turns out I though the article was in Orchids Australia and not Orchids so I'm not able to give it a read. But if I hear you correctly, the article basically says that the most important factor is the cool element and that it is important that it be cool for an extended period. Is that the idea?

[Bolero]

Yes cool without warmth as well, so it should be consistently cool. I think the article is saying that if you get warmth during cool periods when they should be resting it activate the growth of keiki's which is again aggravated by the use of fertiliser.

So it's not so much fertiliser itself but more a case of a cool period getting a burst of warmth as well.

[lmartiny]

I read of dry periods. I admit it is hard to do as a newbie. But I am trying to do that now with a few. A Den Nobile is one. I'm just still confused on how dry? Our temps fluctuate so much. There is no steady cool down. Once thing I definately need to do is group these guys together. Also hard due to lighting and some hang and some are potted.

[berniep]

G'Day

For my info on growing them I used the cultural notes from here Tinonee Orchids as they are only just up the road. I must add the months are Aussie so an adjustment would have to be made for "up over" as opposed to "down under".
As my canes showed no sign of shriveling they required no water.

Cheers
Bernie

[Bolero]

I think the point I am trying to bring to this forum from the article is that although the commonly held belief was that fertilising during the cool period causes keiki's, it isn't in fact quite right. It doesn't look like the study has finished or that it is conclusive but they are saying that fertilising aggravates the creation of keiki's but doesn't cause it.

It's getting a warm burst (as we often do in Oz) of weather which activates the nodes that create keiki's. If we keep it cool then the keiki's won't occur whether or not we fertilise. THis makes sense to me on many levels (I don't think natural fertilisers stop during cold periods) and if the study proves to be true might revolutionise the way we grow these.

[Brooke]

Isn't the Nobile from Oz? Wouldn't they always get the typical OZ winter of ups and downs?

I think most people take a dry winter rest to the extreme unless the orchid really does live in a desert. Night time dew is almost always available to a plant in the wild.

Brooke

[berniep]

G'Day Brooke

Think they come from India and Thailand, may be wrong though.

Cheers
Bernie