Denrobium aphyllum Finding the right balance

[Junebug]

Originally Posted by King_of_orchid_growing:)

You're right and I know you've been doing your homework!

According to the research I've done so far, October is the month to start slowing down waterings for deciduous Dens in their native homelands. Dormancy must be coordinated with temperature drops, changes in daytime length, and the possible dropping (not necessarily) of leaves. Full dormancy is usually reached right around mid-Nov or early Dec and can last from 1 month (for certain species) up to three months from then.

I plan to follow this cycle as well (cross my fingers).

In nature and while in dormancy wouldn't these plants receive a little bit of moisture in the form of dew or perhaps even melted snow? It seems like they would.

[King_of_orchid_growing:)]

I don't know about melted snow (not sure if the places these plants grow in actually snows, they more than likely encounter light frost maybe). But I would imagine the dew drops are more of a possibility. I'll look into this more.

The problem is I haven't found any video footage about Dendrobiums that go dormant in their natural habitat, when they're fully dormant.

I have however read that many people completely halt all watering and fertilization as soon as the plant has entered full dormancy.

But as we all know, cultural techniques are sometimes way far off from what they naturally encounter, and may not even be a close approximation of what the plants are naturally used to (possibly because we're using old data or techniques that may have "worked" in the past, but is now known to be erroneous in some fashion or another, or sometimes we're trying out new techniques, another reason may be that those cultural techniques worked better than what they would encounter in the wild). I'm not saying anything is good or bad here, just trying to give a clearer, fuller picture (trying to look at the bigger picture if you will).

Anyways...

Like I said I'll get back to you on the dew drops, cause I wanna know too.

[Brooke]

They do receive dew in the natural habitat so they do have moisture during their dormancy.

I grow in a g/h, if the sun is out, I spritz very lightly, if there is no sun, no moisture that day. I do this from basicaly mid-Nov. until March-ish - depends upon the growth of the plant.

I never soak the mount nor do I fertilize during the dormant months. I just try to replicate the natural dew they would receive.

Brooke

[Junebug]

Thanks, Brooke. No fertilizer and a bit of moisture during dormancy makes sense to me.

Would you happen to know the cold tolerence of Dendrobium aphyllums? A vendor at an orchid show once told me that in their natural habitat they grow on cliffs at high elevations and that during winter they are fully exposed to sunlight and frigid temperatures.

It's difficult for me to leave an orchid exposed to the elements when the mercury drops below 45 degrees, but perhaps I shouldn't be so protective of this species.

[Brooke]

The natural habitat is mid 40's in winter and very very bright. I hang the mount where the temps get to 56-58 in the coldest weather and it receives full sun. They think the bright light is as important as the dry season.

Brooke

[Junebug]

Originally Posted by brooke

The natural habitat is mid 40's in winter and very very bright. I hang the mount where the temps get to 56-58 in the coldest weather and it receives full sun. They think the bright light is as important as the dry season.

Brooke

Thank you.

[King_of_orchid_growing:)]

Cool! Thanks Brooke.

[isurus79]

I just throw mine in a dark corner during the winter and forget about it. Minimal light and no water seem to work pretty well for me. However, I tried leaving my anosmum (a close relative) out in its normal growing area this year (which means that it is subjected to all the water dumped on Hawaii during its rainy season) on Mauro's advice (who does not with hold water from his anosmums) and I got the same number of flowers this year as in previous years. It makes me wonder how absolute the no water rule really is. I live in an area that does not see temps get lower than 58-60 degrees though. If you get colder temps, then my understanding is that the winter needs to be drier.

[DavidChiou]

some supplementary info fyi:

Denrobium aphyllum's flower grows on 1-year-old canes. Sometimes older canes grow flowers as well but only a couple flowers.

Denrobium aphyllum requires high sun light. It can even tolerate direct sun light if it gets used to the sun light gradually. Full sun during winter can ensure the greatest number of flowers.

In Taiwan (humidity > 50% most of the time), during dormacy, if you grow it outdoors, more than 1 rain per week will reduce the number of flowers. If there is on average more than one rain per week, you need to put it somewhere with no exposure to rain. I am not sure if this frequency makes any sense for your location though.

In case it still has a lot of leaves on before flowering season, you can simply cut all the leaves off, then it can still grow buds for you.

Note that many other dendorium species do not require the dormacy period. I am only talking about Den. aphyllum.

Finally, you can consider to wrap a bag of fertilizer on top of the board. This way every time you water it, it will get some fertilizer. Den. aphyllum can tolerate much stronger sun light and fertilizer than most other orchids. But of course it's always safer to start from less fertilizer.

[DavidChiou]

BTW, in Taiwan, the rule of thumb is that you cut the water supply when the "cold front" arrives (i.e. temperature goes around 50 degree F). The colder, the less frequency of watering. Although this rule of thumb may not apply to where you locate, you can still follow the temperature drop to decide when to cut the frequency of watering.