Update on nobile Dendrobiums in S/H

[Jerry Delaney]

Just wanted to update a thread I started here last August. The question concerned the practice of withdrawing water and/or fertilizer to initiate blooming. The response covered nearly the gambit of potential methods. Old practices die hard and in some people,namely me, perhaps hard doesn't really describe it (right Ray). So, I flushed them a couple of times with just water and early October moved them to the back corner of the greenhouse and didn't start watering again until February. Nearly all flowered but a couple of things occurred that I really don't understand. There were some plants that did not lose so much as a single leaf during that time and flowered anyway. I am kind of taken aback that the plants could go that long with no water and still retain their foliage. Then, again, I had a small seedling of Den primulinum that I watered all winter and it lost it's leaves the same time as those who lost their leaves without water. It seems to me that just withholding water/fertilizer may not be the sole factor in determining if the plants lose their leaves or bloom. I am in need of some enlightenment!

[neb]

What were the temps? I would imagine that has a lot to do with it.

[Ray]

I don't "do" deciduous plants, but my understanding is that it's the application of nitrogen that stops nobile dens from blooming, hence the "stop fertilizing altogether" guidance.

Use of no water or plain water only during the "rest" period seems to be partially a matter of choice, although I have heard others mention that in a greenhouse, watering may not be necessary to keep p'bulbs plump and leaves intact, due to the higher humidity.

[Jerry Delaney]

What were the temps? I would imagine that has a lot to do with it.

Neb, the tray of nobiles were placed at the cool end of the greenhouse while I did not move the primulinum seedling which was at the warmer end. It usually runs around 50 degrees at the cool end in winter while the warm end has a low of 55-58.

Use of no water or plain water only during the "rest" period seems to be partially a matter of choice, although I have heard others mention that in a greenhouse, watering may not be necessary to keep p'bulbs plump and leaves intact, due to the higher humidity.

That may be what is happening. The humidity is high here in the winter so perhaps that is sufficient to keep leaves and plump canes. However, the Den primulinum received water and fertilizer all winter and still lost it's leaves. I guess it's one of those cases of "I wish I understood all I knew about that"! Thanks guys.