Possible to have too much light?

cavanaugh... Since your LED system is 900 watts, perhaps consider an example of intensity from two powerful LED lights and look at Icemud's application regimen as a guide:
~ My 420/990 watt COB/LED SpaceCraft emits about 1500 micromoles at 18" on center.
~ My 740/1760 watt COB/LED MotherShip emits about 1900 micromoles at 18" on center.
 
Schtiggy said:
Yeah, I am not worried about too much light anymore. This is one of my girls on day 23. She has been under about 6000 lumen (per plant) since she was a seed. Seems to like it.

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you want ~ 7,000 lumens per square foot, according to Hosebomber, so you are doing fine :thumb:

The Basics Of Plant Lighting

DankWolf907 said:
100,000?! I better go reread, coulda swore i read 10,000 somewhere.
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Sunlight - Wikipedia

Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux, higher than most artificial lighting, including fluorescent. Multiplying the figure of 1050 watts per square metre by 93 lumens per watt indicates that bright sunlight provides an illuminance of approximately 98 000 lux (lumens per square meter) on a perpendicular surface at sea level
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Hi Richard,

thank you very much for the reply. I will be switching from fluorescent to LED next week. I spent the last few weeks learning everything I could with the main focus being on CFL. Now I will have a whole new lighting arena to try and conquer :)

Ice, you mentioned the likelihood of Mg deficiency with LEDs (outstanding explanation of the principle, by the way). Do you treat proactively for this by, say, adding some calmag every other watering or so, or do you watch for early signs of deficiency and treat as needed?

Thank you very much
 
Hi All!
I'm from Russia, I communicate with Google translator.

Icemud said:
optimal is 800-1100 micromoles PPFD without added CO2
800 - 2000 micromoles PPFD if supplementing CO2.
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Does it make sense to add CO2 has, if the light intensity is less than 1100 umol / m2 / s?
 
doctor green said:
I completely understand what your saying and the linen's lol is my phone changing lumens with it's ridiculous auto correct, you can do as much technical "research " as you like, do you understand when I say none of this means anything unless you have actually applied the light in the real world on your plant to find it's own saturation point, different strains take different amounts of light.

I don't mind what terms people use to "measure "light heck it could be footcandles, real world experience will benefit any new grower more than something they have read but not applied.

I'm not saying you are wrong.

I'm saying that all information read, needs to be put into application and tested to gain you any experience, I suggest also that you come and have a look at my journal and my monster of a plant that can easily take 6 x 600 w in a 2x2 m tent and thrive so you know the point I'm trying to make
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Actually the "terms" that people use to measure light intensity are VERY important... ex, lumens primarily measures light between 500 and 600 nm which is outside both veg and flowering range of light, whereas PPFD measures the entire PAR spectrum (400 to 700 nm). PPFD provides a rationalization of PAR in the context of a horticulture application.
 
Thanks for the responsiveness, SuperFunker.
There were difficulties with the translation, as I will understand, I will write.
 
Benjamen said:
Thanks for the responsiveness, SuperFunker.
There were difficulties with the translation, as I will understand, I will write.
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Since IceMud has not replied, I will offer an answer to your Q:
Generally, at an average light intensity less than 1100 PPFD, you may not generate a significant benefit from adding CO2. If you are at a 'sub-maximal' average of 1000 PPFD across your canopy (not a peak measurement, but an average measurement), you may be approaching light intensity that would start to show a benefit from adding gas. Consider the cost of adding more lights compared to adding CO2. Depending on your environment, it may be more cost-effective to add gas and explore the associated potential.

Ideally, a professional farmer would like to know at what PPFD level does it become advantageous and cost-effective to add gas instead of more lights. Anecdotal evidence provides some general guidelines, but this question has not yet been fully answered by REAL research. A comprehensive study that combines various PPFD intensities using broad spectrum light with various CO2 levels needs to be conducted.

Chandra appears to be at the forefront of this sort of research, but he has not yet answered the aforementioned. If there is some REAL research that addresses the above, please provide links.
 
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