Help with Sophronitis Coccinea care UK

[Pippa]

I have had a Sophronitis coccinea var rossiteriana for about 5 years now. When I got it, it had two leaves and two small roots. It now has lots of roots but still only 6 leaves and it has never flowered. I was told that it would be slow growing, but should it be this slow?

It is in a very small pot, grown in the little hydroponic pebbles, which is how I was advised to grow it. It gets a monthly feed with orchid food when it is growing actively. It lives on a shelf in the kitchen, which is south facing, so very sunny and humid, but not in full sun.

Can someone advise on how best to care for it? What am I doing wrong? Or do I just need to be more patient?

[Roberta]

The light and humidity conditions sound fine. They may not be getting enough of a chill. I don't have that particular variety of S. coccinea, I have a "big" 4N. And also have some other species (cernua, mantiqueirae, brevipedunculata, wittigiana) that also bloom for me. What they all get is a significant chill in winter (2-4 deg C at night) and fairly cool nights in summer (18-20 deg C). They seem to be able to tolerate warm days, but really prefer cool. They're also getting a fairly significant temperature variation between day and night. So I think that temperature, and temperature variation, are factors to think about, to make what adjustments that you can.

[Pippa]

Thank you for the advice. We probably don't get quite that cold overnight in winter - the thermostat is set to 10 degrees overnight, and although there is no radiator in the kitchen, it's a tiny room and will get heat from the adjoining dining room. I'll have to move it to another room for next winter.

It is a problem for plants that like to be cold but not freezing here - in my last house, I had a glazed porch and utility room, so I had a real variation in temperature, but here, even the unheated rooms pick up a bit of warmth from the rest of the house.

[Roberta]

That still sounds like enough chill - they don't need to freeze, it is more the variation in temperature that helps blooming. That actually sounds like a nearly ideal spot, so maybe just patience...

[rbarata]

Originally Posted by Roberta

What they all get is a significant chill in winter (2-4 deg C at night)...

I've read, in the Baker Culture sheets (if I'm not mistaken) that the mim temp that coccinea can be subjected to is 8°C. Considering this, I have been extremely careful about temps below 10°C. I only got this plant 6 months or so ago so I am a newbie in this species.

[Roberta]

Originally Posted by rbarata

I've read, in the Baker Culture sheets (if I'm not mistaken) that the mim temp that coccinea can be subjected to is 8°C. Considering this, I have been extremely careful about temps below 10°C. I only got this plant 6 months or so ago so I am a newbie in this species.

I am very glad that my plants can't read... they really can acclimate a bit outside the given ranges, but it is important that they do have a chance to do that before subjecting them to the extremes. (The species that is more concerning is S. cernua, ideal is warmer than S. coccinea but I have found that to do just fine outside for me too.) But given the Baker notes, 10 deg C likely is not a problem but actually better.

Just checked the Baker sheets in Orchidwiz ... lists habitat temperature range for S. cernua as 8 C - 39 C . (Mine go a good bit lower) but for S. coccinea the given low temperature is -4 deg C (24 deg F), there's an error in the high... given as 105 deg F (reasonable) should be 40 deg C, the sheet in Orchidwiz says 24 deg C which is certainly not right. I certainly don't push mine that hard at either end of the range.

Are the Baker sheets different from orchidculture.org? Errors do happen in transcription...

[rbarata]

In my OW the Baker sheets say about coccinea:

TEMPERATURES: Summer days average 83–84F (29C), and nights average 57–64F (14–18C), with a diurnal range of 19–26F (10–15C).

REST PERIOD: Winter days average 68–71F (20–22C), and nights average 48–49F (9–10C), with a diurnal range of 20–22F (11–12C). These temperatures represent about the coolest conditions under which this species should be grown. Because of the range of habitat distribution and elevation, plants should adapt to conditions 6–8F (3–4C) warmer than indicated. Although rainfall in the habitat is somewhat lower in winter, the habitat remains very wet because of heavy dews and mist from condensation that occur throughout the year. Water may be reduced somewhat for cultivated plants in winter, especially those grown in the dark, short-day conditions common in temperate latitudes. Plants should never dry out completely, however. Fertilizer should be reduced until water is increased in spring.

My OW version is 3.0.

[Roberta]

We look at different parts of the Baker sheets... I look at the temperature extremes for habitat. (I have found that the text in the culture notes tends to be far too conservative. The habitat temperature ranges however sometimes are rather inaccurate because they don't necessarily reflect the actual habitat. But I do find, more often than not, that they indicate what I can get away with. (And I am a "What can I get away with?" grower...)

[rbarata]

I look at the temperature extremes for habitat.

I see...mine says the same...that's a typo for sure.

[Roberta]

Given that my usual go-to source for habitat/culture information has inconsistent information, I figure that we need another source... It was a good chance to visit Compendium of Miniature Orchids. (C. coccinia definitely qualifies as a miniatue) A 4-volume NOT miniature set of volumes, with detailed habitat information by species , as well as culture recommendations. Intermediate to cool, can tolerate temperatures down to 2 deg C, suggests that ideal high should be kept below 27 deg C. (Mine does go a bit higher but not by a lot). High humidity, "bright diffused" to medium shade.