View Single Post
Old April 13, 2018   #27
nbardo
Tomatovillian™
 
Join Date: Jan 2018
Location: St. Louis, Missouri
Posts: 78
Default Grow light questions

Most white LED lights work similarly to fluorescent lights in how they produce white light. If you look at the LED when the light is off, if it looks like a yellow plastic material it works like fluorescent. Meaning the LED itself is producing light in the blue or ultraviolet spectrum. Then they put a phosphor coating on them (the yellow plastic bit in LED or the white powder inside a fluoro tube) that gets excited by the blue/UV light and emits a different color of light that we can see. Different phosphors used will give off different wavelengths of light, so a mixture is formulated to give out a mix of wavelengths that average out to the 2700k, 5000k, etc colors that are marked on the packaging. White LED tend to have a more continuous spectrum of light than Fluorescent, which has more concentrated spikes at certain wavelengths.

Of course there are other white LED like philips hue that combine red/green/blue leds to give off light that looks white, and these will just have spikes at red/green/blue instead of the continuous spectrum.

Then there are the grow light leds that are a combo of blue/red diodes that obviously are concentrated on those very specific points in the spectrum.

So my takeaway after reading a lot about this is that fluorescent lighting produces light that is somewhere in between the discrete spikes of the blue/red led arrays and the more continuous white LEDs. All three work well for growing seedlings, so no need to worry too much about which type to go with. If incandescent bulbs didnt put off so much heat relative to the amount if light they give off they would probably work fine too.

Just one more thing, white LED can “burn” your plants if you use too much power too close to the plants. They can pack a lot of power into a very small concentrated space, so be aware of that if you are using them. You may not want them directly on top of your plants like a fluorescent tube if they are strong lights.

Sent from my iPhone using Tapatalk

Last edited by nbardo; April 13, 2018 at 12:47 PM.
nbardo is offline   Reply With Quote