Light adaptation - Orchid Board

rtsingleton · #1 11-16-2008, 10:59 AM

In everyone's experience, how much have you been able to adapt orchids to more light than 'should be' allowed on them? I'm sure it varies by species but I was just curious as to overall how much you could slowly acclimate orchids to more and more light, if possible at all.

Ross · #2 11-16-2008, 11:02 AM

Sure it's possible. I grow my Phals right now (I only have three at the moment) in a south window where they get full sun when it shines. The leaves are pretty light and reaching for the window. The temps drop to approx 60 degrees at night. The plants are in spike right now.

Aceetobe · #3 11-16-2008, 03:07 PM

There is a component of heat involved.

I have several zygos, and I've had them out in full full sun all day for a couple years. They are fine, grow well, bloom a lot. Once the temperature jumps they get burned though.

As long as the leaf temp doesn't get too hot, most plants can take a lot of light - as long as you slowly adapt them. You really have to watch the watering and humidity in the high light situation because they dry out super quick. Another thing to pay attention to is the root temperature. Clear pots plus direct sun is lethal.

Tsuchibuta · #4 11-16-2008, 03:22 PM

I put all my Phals outside with the rest of my plants and some of them got nearly 5 hours of full sun with no damage and actually are spiking now. I agree if you slowly acclimate them most can take alot of light. I think it's like us we will "burn" less if we slowly acclimate to the sun, but I think in both cases that the intense light will speed up the "ageing" process. As I have noticed that in my plants that usually grow in less light seem to grow faster and loose leaves faster than those in lower light. That being said, I would assume that more fertilizer would be needed as well as the plant would be using more energy in full sun. Though I am no botanist, I just grow based on my own observations.

Ross · #5 11-16-2008, 03:27 PM

Something I forgot to mention, I am at 45 degrees Latitude in Michigan. The original poster is in Texas. One is from Ohio. Those are at differing latitudes. When I say "full sun" that light is probably half strength of Texas light. Once again I must state, a light meter (a good light meter) is the only definitive answer. I measure 3500-4000 foot candles in full sun. If others posting an answer would do the same then the original poster could get a better picture. Just my 2 cents.

Aceetobe · #6 11-16-2008, 03:39 PM

I'm in San Diego. I'm guessing my Zygos get > 6000 fc for about 6 hours a day. Once again though, I run around like a madmen to take them into shadier environment when the temperature is over 85 or so.

Ross · #7 11-16-2008, 04:08 PM

Quote:

Originally Posted by Aceetobe

I'm in San Diego. I'm guessing my Zygos get > 6000 fc for about 6 hours a day. Once again though, I run around like a madmen to take them into shadier environment when the temperature is over 85 or so.

See, that's my point! 6000 FCs is really high. I couldn't generate that even with high output t5 lamps. Most I can get is 4000+ FCs. So if I say "high light" or "full sun" that is way different from your situation.

rtsingleton · #8 11-16-2008, 08:35 PM

If they were in full sun where I am during the hot days of summer the leaf temperature would probably reach 110-120... Cooling a portable greenhouse is a complicated situation...

Ray · #9 11-17-2008, 02:06 PM

Some plants don't bloom as well in excessively-bright sun - just too much stress, I suppose.

isurus79 · #10 11-17-2008, 05:21 PM

When increasing my plant's sun exposure, I will do one of two things. The easiest one is to find an area where the sun in slowly shining longer with each day. This allows the plant to get exposure to bight sun on the sun's schedule. Another trick I use is to put one of my plants in an area that is protected by some natural foliage, usually a tree. Ill put it in a very shady area and then slowly move the plant into brighter areas very slowly. I might move the plant an inch or two a week. Of course I grow in Hawaii, so because of my latitude, I have to worry about the strongest sun in the US! I would imagine though that Texan sun is very strong as well. I used to live in AZ and that sun is brutal! Either way, slow and steady is the way to slowly move your plants into brighter conditions. Be sure to observe your plant VERY closely when doing this. Your leaves will either turn red/purple or turn a lighter shade of green. If you start to see rapid yellow or even black, pull your plant back! It takes a few singed leaves to get the hang of it, but once you do, its a handy trick to know!

Overall, Ive found that most orchids thrive in light that is brighter than what is usually recommended. I constantly see dark green leaves on plants, a sign of dark conditions for orchids. Most people dont give their plants bright enough conditions. In fact, from Q's on the OB and from talking to people, I would say that the number one reason a plant does not bloom is because of a lack of bright light. IMO many orchid culture websites and sources seem to recommend the lower end of the brightness spectrum when recommending light levels for individual species. For example, Internet Orchid Species Photo Encyclopedia is a great website, however, Jay Pfahl consistenly recommends light levels which I feel are waaay too dark and usually push my plants to go brighter. It works great for me! Just remember to slowly acclimate your plants to brighter and brighter conditions.