99% of all led lights on sale today have more than enough blue light in their spectrums for vegative growth.
"white" lights combine veg and bloom functions so they're a compromise solution (I realize that every product is a compromise) by bringing in the spectra from veg lights and bloom lights. Veg (blue heavy) and flower (red heavy) lights directly impacts the morphology of the plants - blue make plants "short and stout" whereas red photons promote cell expansion. I can't cite the source but it's from one one the, perhaps, dozen research papers on my computer, but if you flower with <4% blue you will tend to get malformed foliage. That tidbit may have been in the Bugbee paper where he publishes the reduction in yield as % blue photons increased from 4% to 20%. Given that blue inhibits cell expansion in cannabis, it's not a shock that yield is reduced but what was interesting was that at 20% blue, which is a not uncommon percentage, yield was down by 10 or 15%.
That's part of the compromise of a "white led".
The other part is that, seeing that red photons encourage cell expansion, plants that are vegged with white LED's will tend to be taller than cannabis plants that are vegged with light that have a higher percentage of blue, as in a veg light.
In Bugbee's most popular videos he describes it as light quality impacts plant morphology while light quantity impacts yield. Everything I've read since I saw that video 2 years ago confirms that (I'm sure Bruce is relieved that I agree with him…)
That's sarcasm, BTW.
To address your statement, yes, there's enough to support vegetative growth but that statement glosses over the complexity and the tradeoffs involved.
take what led growlight manufacturers and vendors say about "flower" and "veg" spectrums the products they're selling with a huge pinch of salt...
FTFY.
I agree. The internet makes a lot of information accessible but I get the feeling that consumers today, because of the incredible increase in wealth/disposable income, just don't bother to "look things up" and, many times, unfortunately, they part with their money for a product for which they don't get good value. Grow lights are one of those products where that happens. It's painful to read a grow journal from someone who has a Charlie Brown Christmas tree type cannabis plant even though they bought a "600 watt LED" on Amazon for $59.99 and can't figure out why their plant is so small.
Last night I watched a representative from LEDTonic display his complete ignorance about grow lights and plant biology. He rattled on for at least 5 minutes about how growers didn't need to worry about "veg" and "flower" lights anymore because all of that was taken care of by white LED's. I did not expect him to go into the details about the impact of blue vs red on cannabis and then on growth and yield. For one reason, he would have to admit that his product is, in fact, a compromise solution. A reasonable buyer understands that because every product is a compromise. No, he decided to either lie through his teeth or he truly is completely ignorant. He stated that "in the old days" growers used MH in veg because the blue photons stopped plants from flowering and then they switched to HPS, and others, because the red heavy spectrum of the flower lights made cannabis flower.
It wasn't a parody - the link took me to LEDTonic.com (or tried to) - this pure ignorance, at best, from a spokesman for a company that manufactures and sells grow lights. And the irony is that their light for a 2' x 4' has
superb uniformity*.
*If you try to access their website, you end up in shopify. That's either a really bad bug or LEDTonic is on its way out.
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