says that LED streetlighting is of the wrong frequency to affect plants, I think he means that on the whole, the frequency not going to affect plants. LED growing light frequencies are specifically chosen to mimic sunlight, which is a whole different ballgame.
hmmm - how interesting Here is a graph of the wavelengths of light that plants absorb- You will see that plants generally use wavelengths between around 400-500nm and between around 625-675nm
Here is a graph of the frequency output of low pressure sodium lighting and LED lighting-
You can see that for low pressure sodium lighting (the orange line) there is one large spike around 580nm - comparing that with the graph above you can see that light at this frequency is almost invisible to plants. So low pressure sodium light has little affect on plant growth. (High pressure sodium lights have a different frequency output and are used for plant growth.)
However compare that with the frequencies for LED light and you can see that most of the LED light is in the right frequency range to grow plants. So I would say that if the intensity is high enough plants will happily grow under LED street lighting.
Or am I missing something???
Billericay - Essex
Knowledge is knowing that a tomato is a fruit. Wisdom is not putting it in a fruit salad.
That is what I saw too. My guess is that the key factor will be light intensity. Although we see the street lighting as being bright at night it is in fact of very much lower intensity than daylight.
I suppose it also depends whether the relative amounts of red and blue wavelengths matters to plants. The LED street lighting has a much higher proportion of blue to red than daylight or growlights (the latter often look purple).
Doncaster, South Yorkshire. Soil type: sandy, well-drained
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Here is a graph of the wavelengths of light that plants absorb-
You will see that plants generally use wavelengths between around 400-500nm and between around 625-675nm
Here is a graph of the frequency output of low pressure sodium lighting and LED lighting-
You can see that for low pressure sodium lighting (the orange line) there is one large spike around 580nm - comparing that with the graph above you can see that light at this frequency is almost invisible to plants. So low pressure sodium light has little affect on plant growth.
(High pressure sodium lights have a different frequency output and are used for plant growth.)
However compare that with the frequencies for LED light and you can see that most of the LED light is in the right frequency range to grow plants.
So I would say that if the intensity is high enough plants will happily grow under LED street lighting.
Or am I missing something???
Billericay - Essex
Knowledge is knowing that a tomato is a fruit.
Wisdom is not putting it in a fruit salad.