Importance of 460nm red LEDs?

[RackitMan]

Here is something very confusing to me. Many LED proponents loudly proclaim the need for 460-470nm red LEDs over the cheaper 630nm LEDs. I understand that this better coincides with the accepted chlorophyll B absorption peak.

So far so good.

LEDs veg very well given appropriate wattage & color.

So far so good.

LEDs do not compare (generally) to HPS flowering as far as yield. (Please - let's not go off in that direction here. Thank you!)

OK, here is the enigma: HPS has a ton of yellow. No LED grow lamps contain yellow. HPS has lots of orange. Some LED lamps contain a little orange. HPS has virtual no Deep Red or Far Red and do very well - yet this is somehow necessary for a good flowering LED light. Even 'inferior' 630nm red is relatively low in HPS.

Any SCIENTIFIC opinions on this major discrepancy?

The only thing I can come up with is that plants rapidly adapt to the core frequency of the light provided which would put in question the whole currently accepted Plant Absorption spectrum.

RackitMan Reviewed by RackitMan on 03-29-2010. Importance of 460nm red LEDs? Here is something very confusing to me. Many LED proponents loudly proclaim the need for 460-470nm red LEDs over the cheaper 630nm LEDs. I understand that this better coincides with the accepted chlorophyll B absorption peak. So far so good. LEDs veg very well given appropriate wattage & color. So far so good. LEDs do not compare (generally) to HPS flowering as far as yield. (Please - let's not go off in that direction here. Thank you!) Rating: 5

[stra8outtaWeed]

Here is something very confusing to me. Many LED proponents loudly proclaim the need for 460-470nm red LEDs over the cheaper 630nm LEDs. I understand that this better coincides with the chlorophyll B absroption peak.

So far so good.

LEDs veg very well given appropriate wattage & color.

So far so good.

LEDs do not compare (generally) to HPS flowering as far as yield. (Please - let's not go off in that direction here. Thank you!)

OK, here is the enigma: HPS has a ton of yellow. No LED grow lamps contain yellow. HPS has lots of orange. Some LED lamps contain a little orange. HPS has virtual no Deep Red or Far Red and do very well - yet this is somehow necessary for a good flowering LED light. Even 'inferior' 630nm red is relatively low in HPS.

Any SCIENTIFIC opinions on this major discrepancy?

The only thing I can come up with is that plants rapidly adapt to the core frequency of the light provided which would put in question the whole currently accepted Plant Absorption spectrum.

for one 460nm is blue 630nm is red and 660nm is deep red:jointsmile:

so my advice here is to look at my LED's which have 3500k warm white that do appear yellow to the eye and look at my grows! :smokin:

i get great yields for the wattage i put over my plants...but the difference in my units are they use 3w diodes..not the 1w UFO style!

plus the pattern of LED''s are spread out over a 4" x 40" window creating light from many different angles!

too many folks get caught up in the more power of a single panel and applying the same thought as HID...1000w is better than 400w...in LED's it is all about the quality and power of the LED and having a good distribution so you can keep them as close to the plants as possible. This does not work with a LED panel that has all of the LED's bunched close together like UFO or similar lights....if you lower them close it shrinks the coverage so you have to lift higher to increase the light footprint and then lose effective flowering...this is why many say LED's do not work in flower and it is only because of design.

Since i have been flowering with my LED's it has increased the oil prodution and has made my meds more potent...i would love to get my meds analyzed for THC/CBD and CBN ratios because i can feel the difference in my meds. I had spinal cord injury and suffer from severe neuropathy and most peoples meds do not even touch my pain...so i will NEVER go back to HPS!:thumbsup:

plus no heat...no bulbs to buy again...my lights will pay for themselves in energy savings alone.

i have finished 3 grows to completion with yields of 390gr 437gr 357gr with 450w of LED's... the 4th will be tallied in about 2 1/2 weeks:jointsmile:

[RackitMan]

Apologies for the typo: 460 -> 660.

[RackitMan]

Hey Str8,

While I am ultimately interested in results and would like to read more about your grows; as an engineer, I need to know more about the science behind a particular design and the science as currently presented does not jive.

[stra8outtaWeed]

Hey Str8,

While I am ultimately interested in results and would like to read more about your grows; as an engineer, I need to know more about the science behind a particular design and the science as currently presented does not jive.

i'm not an engineer but my results are real world...that is what is important to me:thumbsup:

the one thing i have learned is 660nm is important in getting a good flower run and they are the most expensive diode so many makes of LED lights just selling price alone do not have good 660nm diodes.:hippy:

so the cheap ones are really only good to grow in veg with...this is like comparing CFL to HID:smokin:

[RackitMan]

"the one thing i have learned is 660nm is important in getting a good flower run"

Almost every single commercial grower and most home growers get great flowers (HID) with virtually no 660nm, yet you see no puzzle?

[stra8outtaWeed]

i grew with 2 1000 watt hps...digital ballasts and hortilux bubls and my yields are very close and my meds are stronger...whats to figure out?

i don't need science to tell me my plants are healthier and producing better meds...there are a few folks on here who may be able to explain your question but again my results tell me everything. you are welcome to look at my albums and grow log. :hippy:

plus i am only growing with half the power i did from before and no heat to worry about or cooling!:jointsmile:

[khyberkitsune]

Almost every single commercial grower and most home growers get great flowers (HID) with virtually no 660nm, yet you see no puzzle?

http://www.hidhut.com/catalog/images/600HPS%20Lamp.jpg

I see TONS of 660 there for HPS. In fact there are almost NO lamps (besides monochromatic ones) that do NOT have 660 emissions of some sort.

[DreadedHermie]

I understand that this better coincides with the accepted chlorophyll B absorption peak.

That's incorrect. 660nm is closer to Chlorophyll A's red absorption peak.

LEDs do not compare (generally) to HPS flowering as far as yield. (Please - let's not go off in that direction here. Thank you!)

That's also incorrect. Check the European cannabis boards, especially the Dutch and Spanish boards. There are numerous documented side-by-sides where 1K watts of LED easily surpasses 1K watts of HID. Their only bitch is how expensive quality emitters are. Is uw Nederlandse taal goed?

Rackitman, if you don't want to hear from people who've successfully flowered cannabis under leds, who do think is going to give you any insight about 660nm? Some dork with a 14 watt China panel?

HPS has virtual no Deep Red or Far Red and do very well - yet this is somehow necessary for a good flowering LED light. Even 'inferior' 630nm red is relatively low in HPS.

Also incorrect. The radiation emitted by HPS even includes a generous amount of non-visible IR, AKA "heat."

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[jtsik330]

The graphs sell the LED's themselves. Urban grower has an article showing the same graphs and the average spending cost of both HPS and LED and its swaying me towards LED's day by day. Ventilation is getting expensive these days.