Interaction between light, humidity, and temperature
 

So when we adjust One parameter, it obviously has a knock on effect with the others. I'm asking this related question in regards, Specifically, to my B little stars; but general answers will be helpful for me and others as well, I'm sure.

For e.g., I was keeping my roots at 77*F during the day, via seedling heat mat; off at night brings temp down to my room temp of 73*F. My humidity was ranging between 55-61 (higher if raining outside). My lighting was recently upgraded and I have been gradually lowering lamp to increase fc slowly to max of around 25-3,000 just above orchid; have a bit more to lower, as have been lowering every 3 days or so...making sure no signs of burn or stress on leaves. Also note that light is a cfl bulb and puts out little heat, which I normally (based on hermit crab and betta/fish care) wouldn't expect to alter the humidity that much.

As my humidity drops though, esp as it will in Winter with heat on, an added humidity tray adds about 5+% to baseline. But it Also drops my root temp, even with the heat mat, down to 75*F.

Since my B little stars is very young, and the roots are only now getting close to going into the media (all Original roots were dead)...which is Most important at this point?
Humidity (if so, best range)?
Temp (or is as low as 72-75 still acceptable)? And speaking of temps...what do orchids respond to, actually? Root temp or Leaf temp, or Both? Anyone have any links to any reasearch papers on this sort of thing?

Any info is greatly appreciated, and if anything I'm doing looks too far off let me know (with the Reasons why, please).

Thanks 🌞

Although each parameter is somehow related with each other, their interaction in an environment is something really hard to explain (considering all of them).
The best is to learn it by trial and error. Introduce sligth variations in one of them and observe how the others change.

Especially with a B. nodosa or B. Little Stars, you may be over-thinking things a bit. Nodosa in it's native locations can live in hot dry scrub within reach of salt spray from the ocean.

I often tell people that benign neglect is a good standard to live by with tough plants like this.

Generally though, plants will take up more water during the day while they are photosynthesizing. They will also transpire more water from the leaves, and this will increase humidity near the plant. I don't know if any of the plant transpiration cools the plant, but moist media and a damp clay pot will evaporatively cool the root zone, especially if the air is dry. Unless it is bone dry winter air, I don't worry too often about humidity, but I would probably be more concerned if I lived in Arizona instead of Georgia.

Ok, thank you. I wouldn't think that a temp drop of only a couple of degrees would matter (unless 72-75 is too cold for constant range)...but the humidity being a bit higher could help with growth or water loss with the higher light, esp during the Winter when my apt humidity drops into the low 30% range. So I think I'll just set it and forget it now...as long as the orchid still looks good.

---------- Post added at 12:25 PM ---------- Previous post was at 12:21 PM ----------

Thanks for the explanations.

I guess I was thinking ahead to Winter when my apt humidity drops into the low 30% range, as mentioned in my reply above. And I was concerned maybe my temps are too low. But I've gotten replies to some other posts and it seems like my parameters are just fine. Certainly my orchid's growth would seem to indicate that!

So I'll aim for the benign neglect thing.