Did my NOID get sunburned?

[Acharn]

I bought this monopodial with two others about four or five months ago. I don't know why I didn't take pictures of it when it was in bloom -- I usually do. Anyway, I've been trying to give my monopodials more sunlight, and they seem to like it, but none have developed flower spikes yet. I suspect they're spending so much enerby growing new roots they don't have any left over for flowers. I live in Thailand, and the sun is very strong around noon. During the rainy season (May thru October) there's usually a high haze that modulates the sunshine. A couple of others seem to be doing well, but I noticed this discoloration. I've moved the plant to a shadier location, but can't be sure this is actually sunburn. I don't have enough experience with vandaceous types yet.

[Paphluvr]

I would think that you are correct in your assessment. It appears that only the leaf tips on a few upper leaves are affected. You'll notice that they are all on the same side of the plant and that the affected areas all sit at the same relative angle. This is usually a good indicator of sun burn. Were they moved suddenly into much brighter conditions?

[Acharn]

Unfortunately, yes. I have a couple of others that were moved more gradually that seem to be doing OK They have become a rather pale green, which I have read should be a good sign, but I check them every day. I reckon I'll have to find a more shaded area for them in another month or so as we go into the cold dry season. Because Thailand has three seasons instead of four, I have a hard time trying to figure out when I should be looking for various things. January seems to be our "end of Winter," for example. Here it's the end of the cold dry season and just before the hot dry season.

Well, thank you for the confirmation. I had some experience with dendrobiums several years ago, but for some reason I avoided the vandaceous types until this year.

[Chatbud]

C'mon, you're in vanda capital
All Thailand vandaceous strap-leaf hybrids must be shielded from direct sun.

[Acharn]

Originally Posted by Chatbud

C'mon, you're in vanda capital
All Thailand vandaceous strap-leaf hybrids must be shielded from direct sun.

NOW you tell me I guess I just don't get out enough. I guess I just have to accept I'm going to kill a lot of good orchids before I get the hang of it.

[brianwstephens]

Wow growing orchids in Thailand must be so great because of all the humidity!

[Acharn]

Originally Posted by brianwstephens

Wow growing orchids in Thailand must be so great because of all the humidity!

Not really. Checking the Thai Meteorological web site for my town (Nakhon Sawan) I see a current humidity of 59%. Seems to me when I was living in Washington, D.C., the humidity in the summer was often higher than that.

We're near the end of the rainy season right now, but in November we start the cold dry season, when it might not rain once a month but the weather can get quite cold at night; daytimes it will still get up to the low 80s. Then we have the hot dry season from February through May. This year we've had a lot less rainfall than normal, and the farmers are going to suffer from a lack of irrigation water.

My biggest problem is the sunlight is so strong, especially just after noon. The sun is closer to the zenith throughout the year, so it passes through less atmosphere to the ground. During the rainy season there is usually some high haze, too thin to call clouds, that does reduce the sunlight some. I've got a couple of Vandas that get quite a lot of direct sunshine. I wish I had a place I could keep them that was more moderate, but it seems like a choice between no sunlight or too much. I learned the hard way to keep my dendrobiums out of the sun, but I'm still feeling my way with the Vandas.