Led spot light vs "full spectrum"

[Waltermelon]

So, I've been looking at a lot of lights recently and found the led spotlights interesting. There has been a lot of companies making the white LEDs for grow lights also. They cost quite a bit less than "full spectrum" lights. But my issue is how to guage the effectiveness of these. The color temps are the same as CFLs, so would I judge by lumen output like we do with CFLs? Are they as effective for growing as a CFL? Any experience with white LEDs? I've read mixed results but the new "quantum boards" are all the rage and they are a white light.

[DrPhoton]

I wouldnt focus too much on the spectrum quality of lights but on the radiant or photon flux of the light. Research shows that light quantity is more important than light quality.

Have a look at my article on light technologies for more information.

[RosettaStoned]

It's the Samsung lm561c diodes on those quantum boards. They have great efficacy (lumens/watt) and that's what is suppose to make them good. I have seen some nice grows with just them. Can't attest to the bud quality though.
I found a great deal on some lm561c strips, one and two foot, and was going to play around with them when I can afford some drivers and such. The boards can be hard to find if you have a specific kind you want.

[DrPhoton]

Are these quantum boards the same ones used in the chil LEDs ?

[RosettaStoned]

Not exactly, they use the lm561c diodes but they also mix others in there as well.

[DrPhoton]

Did i miss a post, i thought KingKush stopped by ^.^

[DrPhoton]

What was the textbook ?

The suns intensity fluctuates throughout the day, with it climbing over 2000umols at the height. Plants typically drive down photosynthesis when the suns intensity is too high. They constantly shift between co2 limited and light limited states

Dont be offended with the large amount of information, thats just what i do. Im not trying to force anything, you had a question and i thought the information would be helpful.

[KingKush]

DrPhoton All information is welcome I was caught up reading and forgot to include more in my response. Sometimes less is more.

I opened up some college textbooks the other day and I was on this subject and it was fresh in my mind. Facts are perhaps, the hardest component about cannabis to communicate but thanks to you its never a dull moment when you are in the conversation.

McMahon, Margaret , Anton Kofranek, and Vincent Rubatzky. Plant Science: Growth, Development, and Utilization of Cultivated Plants, 5th ed. Prentice Hall, 2011

[DrPhoton]

Ima grab that book, some books dont detail the photosynthetic states well, such as compensation point, respiration, saturation point. The page you showed had this and looked well written.

[Waltermelon]

Great article. I do have my basic understanding of light however. The quantity over quality isn't always the case, like halogen quartz. Great output, but mostly useless for growing. I'm not trying to debate, but with all I understand about ppfd and the research done at the University of Mississippi says 800-1500 ppfd is the ideal spot for vegitave growth (obviously flowering should be slightly higher based on photosynthetic surface area) for marijuana crops without co2. But how does that translate to and from "full spectrum" vs white light? Especially with no idea the difference between 5 band, 7 band, 12 band and white light absorption with our crops? Obviously the more bands the better, but the white lights should have the ENTIRE spectrum, but the reviews compared "full spectrum" vs white LEDs all say "full spectrum" produces better results. I hadn't seen a peer reviewed study yet only buds sent from a side by side grow tested at a "lab". White was said to be the lowest performance vs all others. Could the difference be made up by a higher quantity of light vs more targeted spectrum? I could flood my entire house with white flood lights for the cost of one "high quality" kind led.

[DrPhoton]

Holgen is one of the least efficient light technology there is. Not a very good indicator of quantity. Chandra has the best paper on cannabis photosynthesis which i go over in detail in my "why close light proximity is not so important" article. Might be the same paper you refer to but my interpretation of it is different.

White light is only the color temperature of what our eyes percieve. The spectrum balance to acheive this can be many combinations. White LED is generally considered less electrically efficient than other colors, because green is heavily used to provide the white output which is less efficient than blue or red. However white has a high efficacy to the human eye so the electrical deficiency is counteracted. With plant growth however there is no up side for the use of green. But because white LED is predominating the market, it becomes the best choice for consumers due to popularity.

I suggest you read my articles and then if you have any further questions, come back to me and i will be more than happy to answer.

[DrPhoton]

Just to answer your question regarding flood lights. Dont bother. Although they can and do provide adequate effeciency, their overall output is small in comparison to proper grow lights. They achieve their high intensity through the concentration of light with reflectors and or optical lenses. However do not assume that light intensity equals more energy. It doesnt. The total energy is determined in other quantities. See my light metric systems article for more on that too.

[Waltermelon]

Not much new info in the articles. Again, great for newbies. I'm not saying I know it all by any means.
my issue isn't heat production or electrical efficiency at all. My style of growing is a maxed out tent. That's 1500m/mol per meter squared. I understand that the difference between 1000 mol and 1500mol isnt significant, but 1500 is just a few inches with my set up or for some others the difference between $20, so why not?
If the only difference is the electrical efficiency of heat vs light, instead of targeted spectrum with lower m/mols vs exponentially higher m/mols with a 6000k spectrum not sure why anyone would use a "full spectrum" to begin with.
I'm not a tree hugger by any means and could care less about electrical efficiency, as long as it produces the quality I'm looking for. It looks like I'm going to need 2 more tents and run a side by side...

[Waltermelon]

Uniformity is what I try to achieve with multiple panels and height adjustment. The issue I really have is cost vs benefit ratio of white (cheaper) vs targeted spectrum (outrageously expensive) does the obscene price difference justify it's self? I didn't really want to get into quantum physics or anything that intense. Just looking for someone running one of the boards vs a traditional grow panel. I am appreciative of the help don't get me wrong though.
I haven't read anywhere that higher ppf has a negitive effect on a plants photosynthetic effecency though. I'm interested in that idea and I'll need to check that out.

[KingKush]

Isn't daytime sunlight 2000umols?

[RosettaStoned]

Something like that, I think maybe and some change too