can you have too much light

[aclum]

Hi,

Maybe this isn't quite what you're looking for but you might find it of interest...

A few months ago when I was trying to learn more about LED grow lights, I ran across this website:

http://www.weedfarmer.com/cannabis/lighting_guide.php

It has lots of info on lighting, including the output of specific types of lights, but the notable portion is the following where they mention how a plant getting too much light can experience "solarization" that retards growth.

An excerpt
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Light Requirements of "High Energy" Plants
1000 - 5000 lux Min. necessary for life
10000 - 15000 lux Min. necessary for consistent but sparse growth
20000 - 25000 lux Min. necessary for robust growth
25000 - 30000 lux Max. Efficiency for Sub Tropical varieties
25000 - 50000 lux Max. Efficiency for Equatorial varieties

Plants need 25000-50000 lux too grow fast.

90000 lux Max. Sunlight Intensity on Earth's surface This is too much light, it is not good for the plant. Plants subject to intensities at this level or greater are at risk of "solarization," whereby photosynthesis is retarded. This can happen at noon on a clear Tropical summer day, especially at high altitudes.
------------------------------
(Bolding of text mine)

I haven't done much research but I haven't come across any more info on the plant "solarization." (Not at all related to soil "solarization" but more akin, in a way, to photographic "solarization" in some undefined, intuitive way ).

FWIW,
Anne

[Father'sDaughter]

I just try to mimic the natural conditions -- on at sunrise, off at dusk.

[nnjjohn]

My led grow lamps worked fine for germination which all that time these little led grow lights provided the spectrum needed for plants.. after about five more days , the little seedlings went to the table I set up by a window .. they are doing great,, not sure if they will grow leggy yet.. they look like they are doing fine.. no damping yet. The ones i did pot to cups did get shocked but are looking stronger than the untouched ones that are taller in the tray cells. I read it is okay to send them down deeper in the cups if they are getting leggy.. but so far I do not see a problem.. I heard the more light the less chance they grow leggy .. but i think uv sunlight through the window is enough and the plants are safe indoors.

[Doug9345]

Originally Posted by creister

Krebs cycle is not dark cycle sorry my old memory fades. But plants have a dark cycle in their processes of energy use and production.

The dark reaction doesn't require sunlight directly but mostly occurs during the daylight more or less concurrent with the light cycle. The details I'd have to look up as it's been a very long time since I took biology.

[Tom A To]

If you're retired, like me, you can shuffle your plants around all day long, in and out of the Sun, the shade, the clouds, rain, etc. Then you don't have to worry about electric lighting for very long and they are hardened soon after the first set of true leaves pop out. I spend a lot of time doing this, I think it's some form of therapy. Either that or my life is becoming pathetic.

[Tom A To]

Originally Posted by aclum

A few months ago when I was trying to learn more about LED grow lights, I ran across this website:

http://www.weedfarmer.com/cannabis/lighting_guide.php

Learn about LED grow lights, huh....

[Worth1]

Originally Posted by Tom A To

I spend a lot of time doing this, I think it's some form of therapy. Either that or my life is becoming pathetic.

Everyone's life is pathetic in someone else's eyes.
But I do get the joke.

Worth

[aclum]

Yeah, Dennis,

That's my story and I'm sticking to it !

Anne