Viewing post #524366 by drdawg

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Dec 10, 2013 2:02 PM CST
Name: Ken Ramsey
Vero Beach, FL (Zone 10a)
Bromeliad Vegetable Grower Region: United States of America Tropicals Plumerias Orchids
Region: Mississippi Master Gardener: Mississippi Hummingbirder Cat Lover Composter Seller of Garden Stuff
Light requirements vary species by species and even vary within species themselves. Lumens measure light intensity wereas light spectrum measures wavelength.

There has been a lot of research done that identifies what plants need what sort of light (wavelengths) and intensity to germinate, grow, and flower. Generally speaking plants utilize two sorts of light and for discussion I will call them "red" and "blue". The wavelenghs between the peak red and blue spectrum are more what our eyes see. This "visable" wavelength is something like 430-660 nanometers. At the extremes are UV and infrared, and neither of these are beneficial to plants, and if an overabundance, can cause plant mutation and even death. UV is less than 400 nm and infrared greater than 700 nm. Excess UV mutates cells. Excess infrared burns plants. (For orchid growers and many other tropical plant growers, this infrared is what "sunburns" our plant's leaves).

The so-called "visable" light, the range that our eyes can actually see, are not really beneficial to plant growth/bloom. That means that the vast majority of incandescent lighting won't help you much.

Most plants need a good measure of both red and blue spectrums, and these spectrums are tight. The useful blue is 400-450 and the useful red is 650-700 nm.

For spring and summer bloomers, during the fall our light will go more from the red spectum to the blue spectrum. I'm talking northern hemisphere. As the sun gets lower in our southern sky, the blue spectrum increases. The blue triggers the plants to change "gears" from growing (vegetative) to blooming (budding). For fall/winter bloomers, just the opposite occurs. During the spring/summer, as the sun gets more overhead, there is more of the red spectrum and this triggers the plants to bloom in the fall/winter.

Lumens (light intesity) is a whole other topic.
drdawg (Dr. Kenneth Ramsey)

The reason it's so hard to lose weight when you get up in age is because your body and your fat have become good friends.

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