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March 24, 2012


John Dunn

This professional daylily hybridizer delivered a lecture last year at The Long Island Daylily Society and announced that he'd placed much of his plant stock under LED lighting. I had to wonder just how much of a financial risk he might be taking if the plants reacted badly to the LED specral content versus getting exposure to the sun or to more conventional plant lights.

I don't think he understood what I was trying to say.

George Storm

Unsurprisingly, given the importance of horticulture and the cost of heating/lighting greenhouses, there has been significant research on this topic.
It is clear that earthly chemistry is more important than the spectrum of the sun in determining the use that plants make of incoming radiation.

You can find some information on photosynthesis requirements at http://assets.sylvania.com/assets/documents/FAQ0074-0605.844b0c66-0b11-44c1-b6b5-32218c3e6d08.pdf
Unfortunately, this spectrum can confuse some pollinators, so different lamps may be required when plants are in flower.

BTW - even if their spectrum were somewhat better for the plants (unlikely) LED lamps seem like an expensive way of lighting them - at least at the present stage of development

Roy Plant

If not done already, an interesting research paper would be on the qualitative food production of various plants with light wavelength variation as a parameter

Nathan Taylor

The LED based grow lights I have seen are tailored to deliver the particular wavelengths that plants (in general or possibly specific plant types) grow best under. While your diagram is true of light from "white" LEDs the gaps can be filled in with additional LEDs of varying wavelength. AlInGaP based LEDs can provide much of the red deficiencies seen in your chart.

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