best time to cut den keikis?

[tmoney]

hi peeps,

we have a den. green surprise, which by our research is a nobile group den from yamamoto. the thing is mostly keikis, the mature canes are leafless and growing on them are mature growth with root bundles anywhere from 10 to 30 cm. i should post a pic so you can see what i mean....the plant is a disaster.

so, basic question that i haven’t been able to find a simple answer to, when is the best time to pry off the keikis and pot em separately? they are all mature as well, with 4 to 6 leaves and as tall as the old canes. going into winter im feeling now is not the time. should we wait till spring and new growth/post flower (assuming it flowers)?

thanks for any info

[estación seca]

When they begin new growth in the spring.

[Roberta]

A side issue... when Den nobile (and hybrids) get too much nitrogen, especially when they are slowing down in the fall, they tend to produce keikis rather than flowers. What is your fertilizer regimen? (If it were my plant, by this time of year I wouldn't be fertilizing at all) There is debate (and I don't have the answer) as to whether it is cooling nights in the fall, or reduction of water, that triggers spring blooming. I tend to greatly reduce, but not eliminate water in the coldest months (but I reduce watering of everything when it is cold), and cool nights happen naturally for my plants because I'm growing them outside. For indoor growing, this is lilkely trickier to achieve so I defer to those whose growing conditions are closer to yours to jump in with what works for them. But for sure, these plants are likelier to bloom with modest fertilizer during the spring and summer, and none at all in fall and winter.

[Shadeflower]

Originally Posted by Roberta

There is debate (and I don't have the answer) as to whether it is cooling nights in the fall, or reduction of water, that triggers spring blooming

I believe it is light hours that triggers flowering but I do live in a cool climate. I am meaning to test different temperature scenario's.

I thought it was intersting to see the yamamoto article state that under 14 degrees C will initiate flowers in 25 days (only 1 hour of cooling needed) but they will also initiate flowers if kept over 18 degrees, it just takes twice as long at 50 days.

So to me the debate is not whether temps influence flower initiation. Cold temps affect how fast and how many flowers are produced. One can initiate flowering by reducing temps down to 14 degrees. but the yamamoto article states it is not needed to initiate flowers so there has to be another trigger that they are not mentioning imo.

To me it is light hours or temps that are the triggers. I am certain watering or lack of doesn't trigger flowering but I know lots do swear by it so whatever works, might just be a coincidence that every time the light hours reduce they reduce watering and like magic the dens start flowering shortly after. I tried it, didn't work for me but not all dendrobiums are the same and I still have plenty more to grow so just my opinion at the moment,

[Roberta]

I do tend to lean toward temperature drop as an important trigger for deciduous or partially deciduous Dendrobiums, since I have quite a few species that are in that category that I don't dry out at all, and they still bloom. (Too many to move to different spots where they'll stay dry... a case of "Not broken, don't try to fix..." ) I don't even completely avoid fertilizer, but I don't fertilize anything very much, especially in winter, so that is likely no test. Probably, if they are "resting", not growing, they just don't absorb the little that may be around. If the amounts were higher it might be an issue - they certainly don't need or particularly want it when they slow down. Fewer hours of light could also be a factor, for me there is no way to test either that or temperature as triggers since both just happen. But thinking about where these deciduous Den species come from (higher elevation SE Asia, south west China and the Himalaya foothills) both winter temperatures and winter light also just happen. Rain is much reduced, but there is morning dew so they do get some water. (The deciduous Dens don't come from equatorial regions... Dens from those places have very different needs)

[tmoney]

thanks for the input folks! so, yes we will resist the urge to take a few and separate them now....even though this plant is hurting my aesthetic sensibilities. to your point roberta, no, we haven’t been fertilizing. i read all the articles from yamamoto and so we erred on the side of caution. also have been tempted to move it outside permanently, as we seldom get temps below actual freezing, but in dec, Jan, and feb night temps do get down around the 0 mark. we weren’t sure if this hybrid would tolerate it that low. and we don’t have an intermediate temp space, but do try and keep the heaters low in the winter so the house gets chilly at night, probly around 15 c. figured that would be ok.

but fine, fine, fine....we will leave it alone for now!!

edit to add a follow up question. does anyone have info/experience with drastic and quick temp changes? for instance, would it be a possible scenario to move it outside during the day in winter when temps are above freezing, but then back inside at night to around that 15-18 range? or does the temp drop need to occur during dark hours?

[estación seca]

The temperature drop should be most nights but I doubt it's necessary on every night. I suspect if you left it out most of the time, then brought it back in only on nights expected to be below 10C/50 F, that would be adequate for flowering. I have had some of the hybrids get colder right next to glass.

[tmoney]

Attachment 154307Thanks for the tips all. we took the plunge and decided to just try growing this as a balcony plant. it’s getting dappled sun and nights are getting cooler here in germany. up early due to a bad dream so i just checked the thermo outside and it’s 18 apparently. it’s sort of scary to leave an orchid outside, but i guess it’s something i need to get over.

also included a pic of the offending plant that i took yesterday when it moved out. thanks again, and hopefully with any luck we can update with some flower pics in the spring!

[Roberta]

It is especially important that if you are going to grow it outside, that you leave it there. There is still time for it to acclimate before it really gets chill, but just barely. Then, I wouldn't worry about it until nights get down to about 6 C (43 F), 5 C/41F would even be OK. So there is considerable room for more cooling before you have to worry. In short, it should get through autumn without too much worry, as winter starts to hit, then bring it in (by which time it will have had a couple of months to experience chill. Protecting from rain is a good idea, a dry orchid can tolerate much more cold than a wet one. And once you bring it in, it will still have the short days which probably are another trigger.

[tmoney]

awesome, thanks roberta! that makes me feel a bit more comfortable with it. the balcony is covered so rain has to fly sideways to get on any of the plants. hopefully we didn’t wait too long, but honestly if this thing dies then i personally won’t be too sad about it. i don’t think i am a dendrobium dude, at least not just yet. maybe if it makes it and blooms ill change my mind and all the technical fussing over it will be worth it. i am also a bit worries about bringing aphids in to the house with it, as we have a serious aphid infestation on 2 of our roses that i just gave up on fighting cause it’s almost end of season. but im also expecting this to lose most of its leaves so hopefully it won’t be an issue. this is why i don’t like to have indoor plants outside!