Question re: LEDs

[Ray]

Originally Posted by Discus

I'd love to know if the lack of blue vs. absorption spectrum (probably UV actually) makes a significant difference, particularly for more shade-adapted plants.

There actually isn't a lack of blue in these white LEDs - just the opposite, in fact.

White LEDs are wither blue or UV chips coated with a phosphor that absorbs, then re-emits the white spectrum, much like a fluorescent bulbs. That spectrum tends to be very strong in the blue end with almost no red, which is why I have them manufactured with two "grades" of white, and some red chips.

The lack of blue in the graph is a remnant of inadequate overlaying of two graphs, - they actually start and end at the same wavelengths. I obviously need to improve that.

[NatalieS]

Just a pic of what the diodes on the LEDs look like when they are different whites - cool on the left (more blue spectrum) and warm on the right (more red spectrum).

[Ray]

Check your spectral distributions, Natalie. The only discernible difference in the spectra of all of the "warm" and "cool" white chips I have looked into was the magnitude of the blue peak, with no other sifgnificant differences; neither of them having much red to speak of.