churchhaze
Well-Known Member
Even for lettuce, it seems like the japanese are using R+B for germination only, then using warm white for the older stages. (at least that's what I've always assumed was going on in that picture)

I would start at 3 feet and adjust for responseJust a quick question if anyone could please answer it
I have a couple of seedlings just sprouted in last 24 hours under a 250w cfl how far should the bulb be away from them please
Thanks guys
Can you show us an example of an R+B lamp producing more than an equally powered HPS lamp? I would love to see this "efficiency" from having less green translate into tall, healthy, and productive plants...
If you're germinating lettuce seeds, R+B might be the perfect spectrum, but in order to have a light that can penetrate the top level canopy, green and yellow are needed. If you tried to light 3-4 foot plants with R+B, in order to get enough PPFD (1000-1500umol*s^-1*m*-2) you'd end up frying the top canopy to a crisp because none of the light would penetrate.
Besides that, red light without being balanced by "bad" wavelengths throws shade avoidance completely out of wack as lower branches don't realize they are covered and need to make it to the canopy.
This study shows a BLM 1200 LED using much less watts than double ended HPS growing significantly more weed:
Here is the BLM spectrum used:
https://cdn2.bigcommerce.com/n-pktq...MAX_Chart__27274.1412972277.1280.1280.jpg?c=2
My guess is the spectrum is about 10% blue, 86% red and 4% green/yellow.
I do agree IMHO that green light is beneficial. My opinion goes with the earlier study attached, green is great up to 24%. I have attached another research study on green light that basically states what you are saying... green penetrates.
To get the most out of your lighting, I think you will find SCROG method superior.
Most closet growers can't afford BLM 1200 Spyders or 1000 watt double ended HPS. My goal with WeedBulbs.com is to get the entry price down for closet growers.
More research is needed. Most of the research is all over the board with nothing conclusive leaving us all to form "opinions".
That's a brute strength photon flux advantage and it'd be hard to prove it's from the spectrum and not the fact that it's higher intensity.
I would rather utilize a spectrum of light that is not only beneficial for the plants...but, also a spectrum that is comfortable for me to work under. I didn't like the way I felt when I was running HPS back in the day. I felt great, however, when I was running MH. Go figure!As far as working around and under intense purple light goes, I wouldn't like it. I think it's very possible that long-term exposure to "unnatural" spectrums may be more detrimental to human health than it is of benefit to plant health. -2 cents
White light is typically made by mixing blue, green and red...
- So if you have HPS, add blue light when you are working on the plants... this will make white.
http://www.amazon.com/PowerBLUE/dp/B00YELLHP8
- So if you have purple light, add green light when you are working on the plants... this will make white.
http://www.amazon.com/PowerGREEN/dp/B00YEO6N3G
This way you have the best of both worlds... efficient for plants when you are not around and nice for humans when you are working.
Actually, I would love to SEE (visually) if mixing a green CFL light and a purple light, would, in fact make white light. That would be really cool if it did....but my guess is that it would make something other than white light. But, hey show me and I'll believe it!![]()
In that first video, the plants under BML were getting significantly higher PPFD measurements. The plants under the BML bars had PPFD within the range of 620-1200umol*s^-1*m^-2 while the gavita had a measured range of 570-730umol*s^-1*m^-2.
That's a brute strength photon flux advantage and it'd be hard to prove it's from the spectrum and not the fact that it's higher intensity.
Sounds like a "Sun Spectrum" Secret Sauce is in orderIt actually would be
more electrically efficient to make white light from monochromatic RGB LEDs than to
use white ones. Nevertheless, inclusion of a few white LEDs on an array may have
utility in terms of achieving certain proportions of broad-band color in case green LEDs are not included.
(...)
from here,
http://ntrs.nasa.gov/search.jsp?R=20150009399
What cobs is this based upon?