"winter dormancy"
 

I don't have any plants that require a winter dormancy, but I was just wondering what exactly that means in terms of watering. There seem to be several posts out there from people whose plants were dying because they completely stopped watering or misted infrequently so only the surface of the medium was marginally moist (I guess that works for some Catasetinae but not for most others)... so how exactly do you water during that time period? Around the edges of the pot?

It depends on the plant. In cultivation few orchids do well with a long, completely dry cool season. Catasetinae and Peristeria elata need a long dry spell. Most others should be watered less during winter but not zero. Watering means all the roots. If Cattleya or Dendrobium pseudobulbs shrivel they're not getting enough water.

You have to distinguish between:

A. Slightly reduced watering during winter months. This is simply a reflection of the plants drying out slower during the lower light/temperature winter season.

B. Plants that come from regions with significant dry seasons. One example would be Den. kingianum & Den. speciosum from Australia. These plants need plenty of water (& fertilizer) during spring and summer, but:

• No fertilizer after Sept 15th (till blooms open).
• Watering reduced 90% (I go from twice weekly, to once monthly) from Oct 15th, till buds form.

C. Plants that have a true dormancy period. In addition to Catasetum, this applies to Habenaria and deciduous Calanthes (but NOT intergeneric Phaiocalanthes).

If you read about the natural habitats of many of the plants that undergo a “winter rest”, you will find that they often state something along the lines of “rainfall is significantly reduced, but fog is common, keeping the plants hydrated.”

“Rest” is really more about “no food” than “no water”. I know folks growing nobile dendrobiums and kingianums in semi-hydroponic culture that keep watering year-round; they just skip the fertilizer all winter.

Thanks all! That makes a lot more sense. :)

It is all about understanding the natural habitat of each plant. "Winter Rest" is not something engineered by the orchid community, it just reflects the appropriate cycle of nature for each species.