Purple color on leaves of catt

[Sharyn]

I've been very careful not to give my catts too high of light while trying to accilmate them outside. So far, due to our weather, they sit outside during the day if it's nice (no sun), and come into the house at night. I forgot them for two nights and the temperatures went down to mid 40'sF. After that, I noticed the underside of the leaves are a purple or maroonish color.

I know that too much light or heat can cause the leaves to discolor, but can cold also cause this? They're shooting out new growths & roots and seem to being doing ok, except for the color. It's only the underside of the leaves; the upper parts are light green in color. If it wasn't caused by the drop in temperatures, is there something else it could be?

[Aniko]

Sharyn, I can not answer your question , but the opposite experience gave me a similar result, on the other side...
I tried to move outdoor my Catt.Edisto, as you did with yours.
It was nice sun with a thin layer of cloud (Cirrus), I checked the surface of the leaves = warm, I taught it will be OK, but after a while I found a hot spot.
On that spot the upper surface got purplish (not brown!)

From that time I'm afraid to put it out because I can't control the light intensity (which seems to be higher than I expected in this area).

[Sharyn]

Thanks Aniko. After reading your post, I remembed it was very sunny out and I put the plants in the corner (shaded area). Maybe it was too much bright light all at once? The only other thing I can think of is that the temperature dropping to 45F at night might have caused this. They've been used to indoor temperatures of about 65F. I'll have to be more careful. Right now it's a pain putting them in & out of the house. I'll be glad for decent weather. Thanks for your reply.

[mayres]

I don't have this process totally mastered either, but my method is to cover them with a 65% shadecloth and then slowly over time remove it longer and longer each day. A little purple isn't necessarily a bad thing - as long as you stay away from brown. I found that even the overcast days are unbelieveably bright compared to being indoors! Be careful. They will eventually aclimate if done slowly - as you know........

[Aniko]

I understood that I should try to acclimate gradually...
(This is the first summer since I have this catt and I don't know for sure if the southwest window can provide sufficient light for blooming.I measured the light intensity - it seemed to be enough, but of course not as much as outside.
Oh...it's a great dilemma!)
Anyway, thank you for support and advise.

[Sharyn]

Mike: I actually remembered a previous post of yours regarding slowly getting the plants used to the increased light. I thought I was doing that - guess not very well! As long as I know it's a lighting problem and not cold, I can experiment with the light.

Aniko & I share the same problem of growing indoors for most of the year in a south and southwestern exposure. Getting the orchids used to outdoor lighting conditions slowly looks like it's going to be a challenge. I even checked the fc of light and thought it was low enough to start out. Now, perhaps I'll try a piece of shade cloth. Do any of the home improvement stores carry the cloth? Otherwise, I know it's available online.

Thanks for your help.

[mayres]

Not sure about where you live, but in my area there are a lot of landscape greenhouses that use it and there are some supply houses nearby - you can have them cut any size you want off a giant roll or in my case I purchased a piece of precut 65% that was 16 foot square. It would be nice to have two or three different degrees of shade available ideally. In my case its just try and guess with the amount of off/on and the type of day. When you work and are not available every day to baby sit the situation throughout the morning it is far from ideal and a certain amount of risk is involved. The bummer is that when/if you give them too much too fast and truly burn them - as you all know - we're talking YEARS before they recover and shed their brown leaves. Bummer. About 80% of my plants did well in the transition last year, but a few of them have a year or two to go before they will look good again. Of course I'm hoping for an improved transition this year with not repeats of last year's browning. When in doubt - give them extra cover. In retrospect one of my problems last year might have been watering them in the middle of a hot sunny period and having the water on the leaves intensify the sun/heat??????

[Sharyn]

Mike: Is this what I'm looking for? It appears that they have pre-cut sizes in various degrees of shade protection. Do you think a 50% cloth would be sufficient? My orchids will not be in direct sun - just need something to help acclimate them to the higher light outside.

http://www.gemplers.com/groups/shade-cloth.aspx