Is my Young B Little Stars getting Too much light?
 

Hi. I have Slowly been inching my full spectrum, 27W cfl bulb down toward my young (only just starting to grow a few sheaths) B Little Stars; I recently upgraded my lighting.

It is now around 5-6" from end of bulb to tip of longest leaf. The output at leaf tip is around 1500 fc or bit more (still not Great at getting Consistent readings with my light meter). Light is on for 14 hrs; may decrease slowly to around 12 hrs by Winter (if recommended).

When I first bought her, the orchid had dark green leaves. In my Original distant, but full spectrum Group of 13W cfl bulbs, her leaves gradually got lighter.

As I've inched the Current light (inside a deep dome reflector), they've continued to get lighter. As I got to what I figured would be a Final stopping point of an "ideal" 6" away, the upper edges of her leaves, and esp her biggest new growth, have all gotten darker and darker purple. There is also some more subtle purple splotching throughout.

I know purple coloration indicates the orchid is receiving its high light requirements. But is it Too Much...esp since this is a Young plant with Tiny new growths?

Also, do the leaves look adequately hydrated, or is the potential too much light affecting that as well?

I certainly don't want to cause sunburn and setbacks at this point. (It was a sort of rescue, with roots found to be munched by snails. But sprayed once with H2O2 and no signs of snails now; two new, fat roots look good and growing longer every day).

If I need to move light further away, is there a recommendation as to How far...or just see if purple diminishes a bit (but not completely)?

Is there a point at which purple coloration then becomes sunburn? I mean, any Warning signs, before it becomes irreversible damage?

Thanks 🌞

1500 fc is barely half of what might be recommended for a healthy mature plant of this cross, and your plant is not so young and small that it needs to be babied much. If it seems a bit dehydrated I would be thinking about heat, humidity, media and watering, not light.

I understand the fc reading is half...if we were talking about Outside growing in the sun. However there seems to be quite a bit expressed various places (maybe I can edit with specific examples, though if I'm not mistaken even Ray mentions this on his site firstrays)...that lower, Constant light levels for Longer photoperiods makes up for brighter, inconsistent/sunshine-cloud variability levels.

My understanding, too, is that if my orchid were Not receiving proper light it would be dark green and not growing. Neither is the case here.

In fact, the whole thing I was asking was whether the levels might be Too high (maybe not just the fc but the whole photoperiod issue combined into it)...based on the darkening purple areas.

As far as humidity and temps: isn't 60-70% humidity and root temp of 75 (room temp 73) ok for this cross?
I'm not certain how to tell if the leaves are indicating dehydration, which is why I asked. (Would they be folded up more?)

It seems the orchid is growing really well, incl three new sheaths. I just didn't want to cause it to get sunburned, trying to get her light levels higher. That was my Main concern.

Thanks.

I think your plant is on the lower end of it's light requirements, and may not bloom as it is right now. When you start seeing purple coloration and/or freckling, you've hit your plant's sweet spot.

In my experience, orchids just below their optimal light levels actually grow very well - the problem is that you won't see any blooms.

Yes, constant light for longer periods can somewhat make up for low intensity. That still probably puts this near the low end of what would be recommended. Purple coloring would indicate you are getting close, but I don't see a significant amount of that in your photos. I don't think you are close to sunburn level.

Root zone temp should be fine, but I'm concerned about the leaf temperature near the light. Unless you have very good air movement it can be much warmer. The leaves don't look badly dehydrated, but perhaps a bit less plump than I would expect.

I have to agree with the previous assertions your light is too low for this cross, much less for sunburn! When your mature leaves get more purple spots and the new growth is darker purple, you'll know the plant is receiving adequate light to grow and bloom well.

Ok thanks, everyone!

I think the Pics don't clearly show the Degree of purple...but it certainly sounds like I don't have to even Remotely worry about sunburn 😜

I Do have lots of air circulation and with the cfl there's very little heat emission. Tips of leaves are cool. Temp per thermometer is same as lower down on plant.

As for hydration I am switching to semi hydro for a bit more evaporative effect And because I have issues with bark overall/don't want to disturb roots with reporting. But with roots and new growths just growing it's perfect timing.
It also will obviously make a huge difference once there's actually roots In the media...to be able to uptake moisture directly!

I will continue to monitor overall growth and reaction of my gal. I'm happy, and able, to add a Second lamp if needed. (But if my pics were more accurate, I think it'd show that "sweet spot" mentioned. In fact, I noticed More speckles just this morning. Just FYI, I only just maxed the light less than a week ago, so maybe my orchid is still adjusting?)

Thanks for all the Very Helpful info...and resssurance about the sunburn question. I'd rather add More light...than cause an irreversible sunburn and set my gal back after all we've achieved thus far!

Cheers 🌞

I don't think it's possible for most orchids to sunburn with CFL lighting. Certainly not a Cattleya alliance plant.

Thanks, ES. I'll cont to adjust lighting as needed. Will send out updates at some point.

Appreciate everyone's help 👍🏻

Ah, that's an important piece of the puzzle! I bet it will get darker over the next few weeks.