Water or not to Water

[RDtrack]

I recently purchased two Dendrobiums, my first dendrobiums. One is a Dendrobium - Phalaenopsis and the other a Dendrobium - Bigibum x All Season Blue (I believe its a miniature).

Light - Currently they are blooming and I have this in a east facing window (So good morning sun, sometimes direct).

Water - I've read a lot of care sheets about these orchids and I'm confused on the watering pattern I should use. I'm use to my Phal. that I water ~1 a week, which is what I've been doing with the Dendrobiums, is this appropriate or should I stop? I've read you only water once a week or maybe twice a week when they are growing/producing their bloom stalk and then quit watering when they are blooming (only until the cane shrivels), should I follow this advice? Also I normally mist this in the morning (I don't have a humidity tray for them as of yet), is this alright or should I quit that too?

Also will the type of Dendrobiums I have loose their leaves after they bloom? Or should a new bloom stalk emerge from in between the leaves as the current ones are?

Thanks for all your help.

[gnathaniel]

Originally Posted by RDtrack

I recently purchased two Dendrobiums, my first dendrobiums. One is a Dendrobium - Phalaenopsis and the other a Dendrobium - Bigibum x All Season Blue (I believe its a miniature).

Light - Currently they are blooming and I have this in a east facing window (So good morning sun, sometimes direct).

Water - I've read a lot of care sheets about these orchids and I'm confused on the watering pattern I should use. I'm use to my Phal. that I water ~1 a week, which is what I've been doing with the Dendrobiums, is this appropriate or should I stop? I've read you only water once a week or maybe twice a week when they are growing/producing their bloom stalk and then quit watering when they are blooming (only until the cane shrivels), should I follow this advice? Also I normally mist this in the morning (I don't have a humidity tray for them as of yet), is this alright or should I quit that too?

Also will the type of Dendrobiums I have loose their leaves after they bloom? Or should a new bloom stalk emerge from in between the leaves as the current ones are?

Thanks for all your help.

Hi RDtrack, how you should water depends on several other cultural factors, especially how the plants are potted, how much light and air movement they get, temperature, humidity, etc.

In general this type of Dendrobiums (hybrids and species within and between sections Phalaenanthe and Spatulata) seems to like warm to hot temps (though they will tolerate pretty cool if kept dry), high light, and to have their roots dry off very quickly. I've had my best success (ie not killing them in a month!) potting them in 1:1 LECA or stone and coconut fiber chips. I think they'll also do well mounted on a xeric-appropriate material like cork or a stick.

If they're actively growing and you can keep temps and air movement high, water frequently (but let the roots dry out between), and if it's not growing or is cool water less. One caveat: new growths will often rot very easily if they get wet--some sources recommend not watering at all until new growths have their own roots going.

If these plants are happy they typically won't go deciduous until individual canes get pretty old (like 3-4 growth cycles). Losing leaves is often the plant's response to water stress because it minimizes water loss through transpiration (note that water stress is ironically often caused by rotted roots!).

These have a pretty different lifestyle and growth cycle than some of the other sections of Dendrobium, which is one of the largest and most diverse of orchid genera. Most sources do recommend giving these a dry, slightly cooler rest at least once or twice a year after each generation of new growths matures. This helps initiate a new growth cycle when temps warm and moisture increases.

The couple of plants I have in this section tend to bloom first off the terminal node of a cane, then send out successive spikes from 1-2 nodes further down (from between the leaves) if they've been grown well. Sometimes this is in the same growing cycle and sometimes in the next.

Here's a link to one of the better resources on culture of species and hybrids in this section: Dendrobium Species Culture. Just scroll down to parts 2 and 3 for Den. phalaenopsis and bigibbum (though the nobile info is excellent as well). Hope this helps!

--Nat