Quote:
Originally Posted by BlueAbyss
Hmm. I'm surprised that no one picked up on this sooner (or commented). Maybe it takes someone who is an avid indoor gardener and 'reefer' to see the similarities.
For effective flowering and fruiting, plants need a fair amount of the red spectrum that is lacking in higher K bulbs (part of the reason those bulbs generally rate lower in PAR).
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Im pretty sure a lot of people noticed... just nobody commented on it?
Not that im trying to cut in to what your saying, but blue light (/wavelengths of light) actually has higher energy than green light, and much higher energy than red light. The larger the wavelength, the lower the energy (blue = 400-450nm while red = 600-690 ish). Recently we determined the rate of photosynthesis in spinach cells when exposed to different colours of light, it occured most effectively with exposure to blue light. The absorption of blue light by the photocells was about 50%, while with red light it was about 12% and green light like 5%. Though green light has a higher energy content than red light, I guess the plants do not absorb this as much? They appear green because they reflect back most of the green light.
So because of the benefit from the blue spectrum, I dont understand why higher K bulbs do not produce better plant growth? You mentioned the red seems correlated with flowering and fruiting? Is that the reason the lower K ratings are preffered?
Also just a note for anybody - The colour temperatures we use with our hobby are simply 'Correlated Colour Temperatures', meaning the temperature we interpret the light to be. If we were talking actual colour temperature, a blue light (around 420nm, like actinic) is actually around 7200 degrees kelvin. A crisp white would be around 42-4700 IIRC? And 'yellow' plant bulbs are in the 3000's. Correct me if im wrong.
Cheers,
Chris