Orchids that require dormancy

[Dulcinea]

Is there a part of the Forum that discusses which orchids need dormancy and how to provide it? One orchid I have is calanthe rosea. I have others also but don't know what their requirements are. Any help would be great!

[Cjcorner]

If you do a search of the internet with the names of your plants; usually you can find information on each plant. It would take a great deal of time to list plant by plant that needs dormancy.

[pavel]

Connie is quite correct. However, as you go along, you will discover that certain groups are more likely to have members that require a dormancy of some type than other groups. As you know, dormancy typically entails a period of drastic water decrease and/or a marked temperature change for a prolonged period. As far as a guideline concerning the more common orchids:

Bulbophyllum alliance -- none that I know of require one

Catasetum alliance -- most require one, I believe ... perhaps all?

Cattleya alliance -- Few to none require one.

Coelogyne alliance -- ?

Cymbidiums -- many do require one -- especially common with the large standards

Cypripedium -- many do require one

Dendrobium alliance -- Many members DO require some sort of dormancy.

Paphs & Phrags -- none

Phals -- none

Pleurothallis alliance -- To the best of my knowledge, none of the members require a dormant period but if there are then the number is very few indeed.

Oncidium alliance -- few to none

Stanhopea alliance -- none that I know of

Vanda alliance -- none

A general rule of thumb is that if the orchid does NOT have a discernible pb, then it will not require (nor generally be able to survive) a dormancy period. If they do have a pb, then they might have a dormancy period.

[Dulcinea]

Thanks. Your information is very helpful!

[raybark]

One question is "how do you define 'dormant period'?"

Some really do go dormant, such as cypripediums, which not only stop growing altogether, require a period of "vernalization", which for me, is being unpotted and stored in the refrigerator crisper over the winter. Others only require a "rest period", which has often- and long been described as a "dry winter rest", when in fact that "dry part" is untrue, but the requirement, instead, being a total lack of nutrition.

[Dulcinea]

Thanks very helpful Ray. I guess I'm lucky we live in the age of the Internet so I can read and research!

[coeruleo]

i grow mostly outdoors in southern california, so my plants get a natural fall/spring but not much of a winter. if it is cold, i withhold water, unless the plant looks bothered. i water very lightly in winter those that cannot take the dryness at all, like vandas, and that is mostly in the form of misting roots in the morning. but the general rule is cold=no water. so my 'winter rest' is a decrease in water and no fertilizer, except cymbidiums and things that still grow. if a plant is not in active growth there is no need for fertilizer. the one exception i have is Dendrbium kingianum. i went from halloween to march only watering once a month, lightly. the canes dried up to little dried twigs, but came promptly back once watering resumed. got 14 spikes and 3 keikis, and the new growths are coming in huge. this winter i will not be so severe and see what the difference is.

[Brutal_Dreamer]

*moved to the Orchids That Require a Winter Rest Section of the forum. There may be other helpful threads in this section too.

cheers,
BD