Catasetum type orchids - flower spike development - lighting levels

[SouthPark]

Hi all!

I recall reading information about catasetum type orchid dormancy - where I assumed that truly dormant catasetum are not growing.

However, when these plants are in true 'dormancy' but is developing a flower spike, then obviously something is growing - ie. the flower spike.

So an orchid growing a flower spike isn't 'dormant' as such, right?

Also - anybody know if these kinds of orchids require regular lighting levels for flower spike development during 'dormancy'? Or could they grow their spike in say 'darkness' (followed by flowering in darkness)?

Thanks all!

[estación seca]

Bump.



I think they use light cues to trigger flowering.

[Roberta]

The only ones that I know of that bloom during dormancy are some of the Clowesias (I know that Cl. Rebecca Northen blooms in around February, on leafless pseudobulbs, does its growth a month or two after the flowers are done. Others may be early, but spikes aren't ahead of the leaves.

"Darkness" isn't a part of the natural cycle of these plants... in nature, it's dry in the winter, but certainly not dark - if anything, it's brighter than during the rainy growing period. They don't seem to need much, if any light, though... they'll start sprouting and rooting when they're ready even in its absence. In fact, I've long been puzzled about what the trigger actually is... many of these come from equatorial regions where days and nights are pretty much equal all year around. They seem to do their rooting and sprouting in anticipation of the rainy season. How do they "know"?

[SouthPark]

Thanks very much ES and Roberta!

This question came about due to a couple of things - one linked to a 'possible' (but not sure yet.... I will have to wait a bit more to see) flower spike developing from one of my Fdk. After Dark plants. But also from cases I've read about catasetum-type orchids producing spikes while entering dormancy or even during dormancy.

While my catasetum type orchids still get morning sunlight on them, I was just thinking about whether the flower spikes of catasetum type orchids require light for growing their spike - or whether those spikes can grow and develop independent of light. I could definitely test in future hahaha - but probably a good idea to ask first - just in case.

This also brought about a question on whether spike-growing catasetum-type orchids during their 'dormancy' are actually dormant.

Maybe the plant really is dormant. And the spike grows independently - and making use of water etc from the pseudobulb. Not sure!

Thanks again for your posts ES and Roberta! Always appreciated.

[jcec1]

I've had cycnoches and cycnodes bloom mid winter months into dormancy, the spikes developed well after watering stopped.

The light levels here in winter are really poor, 6 hours of daylight but mostly overcast and raining, so virtually no sunlight. The spikes develop, more spindly than summer and smaller and fewer blooms, there is no detriment to the plant though.

[SouthPark]

jcec ----- thanks very much for sharing that information. This definitely goes toward knowing whether or not light level plays an important role in the actual growing of the spike (ie. lengthening and bulking up of the spike).

[DirtyCoconuts]

Ok, here is my take.

I grow these outside, under an eave partially, they get full morning sun, slightly filtered mid morning (palm tree) and full sun until 1-2 when it is bright shade for the rest of the day

I have seen the in situ pic of them and they are in damn near full sun (occasionally a palm frond over them) and I am blown away bc it looks like the scariest orchid habitat I’ve even seen

My plants flower with leaves a lot more than without but I have had a few spikes open once the plant is dropping leaves. More grow and spike with all their leaves.

I have three spiking now and two that just started random new growths too?!?

I have played around with making a sort of palm totem to mount one of them too and see how that works!! I have a lot of palm and though about making a three or four foot length on a platform and then seeing how it does with no interference from me once it’s mounted.

Back to the question. I have also no idea what the trigger is but I do think It is more temp related than light. The diurnal cycle is pretty stable where they grow but the temp varies quite a bit. (As Roberta pointed out)

[SouthPark]

Thanks DC! Very nice information too, and thanks for sharing that information.

When the spike first begins to grow - starting from the little rounded stub, and then gradually progresses to the buds and flower-opening stages ----- it sounds like the intermediate and late stages of spike growth require light (or enough light) to keep things rolling with the spike growth.

[DirtyCoconuts]

maybe the spike does not need the light to initiate but it does to develop and know which way to grow???

---------- Post added at 11:12 AM ---------- Previous post was at 11:07 AM ----------

monn milleniun witchcraft and an SVO (first bloom for me ) hybrid [tigrinum'SVO' x kleberianum'SVO'] both growing in the same orientation which is to the brightest light they get

Vanda by J Solo, on Flickr

Vanda by J Solo, on Flickr