Length of time in light

[april]

Can someone please enlighten me on the subject of light for my babies? I see from the charts that my Vanda requires a lot of light. How do you know how many hours she should get that intensity?

[billc]

Hi April, Try this link and you will be enLIGHTened.
Comprehensive Culture Guide—Light levels for growing orchids
Good luck with your vanda.

Bill

[King_of_orchid_growing:)]

I wouldn't expose them to full sun the entire length of the day. They should be a bit shaded during the mid afternoons.

[Ray]

Originally Posted by King_of_orchid_growing:)

I wouldn't expose them to full sun the entire length of the day. They should be a bit shaded during the mid afternoons.

That depends a lot where one lives. Here in PA, I can do that with plants I've acclimated to the light levels, but when I lived in SC...no way!

Plants need a "mass" of light in the correct wavelengths. By "mass" I am referring to number of photons reaching a specific area over a period of time. Most of the time we think about intensity, which is number per unit area, so can deal with just two variables, that and time of exposure.

If we are growing under natural light, we often have to control the intensity via shading, as too much light intensity can generate too much heat for the tissues to dissipate. Under artificial light, it will depend upon the source and distance from the plants.

Extra time can compensate for lower intensity, but only so far, as plants need "down time" for certain biological activities to proceed, and some are actually stifled by incident light. From what I have read, 14 hours seems to be the practical upper limit.

[KarenAnn]

Question for you, Ray. I am in CT. Last summer I had my vandas under 50% shade cloth and did get some to bloom, but I'm wondering if that's required since I'm in the NE. I also have some renanthera...