I agree, very nice
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LED and BUD QUALITY
- Thread starter Tropical Sun
- Start date
CharlesU Farley
Well-known member
Can't remember if this has been posted in this thread before, don't have the time to plow through it to see, If it has just ignore this post.
I never had the luxury of keeping my 1kW MH light _four_ feet from the canopy in my 2x5 closet. And in the tents downstairs, depending on what I'm trying to accomplish, I put my LEDs two to three inches away from the top of the canopy during flowering but sometimes 3 plus feet away in veg, to encourage stretch/height.
Here's the take away from the study:
"...at the suggested distance from bulb to canopy in the HPS versus LED comparison (6 inches for LEDs and 4 ft for HPS), carbon assimilation rates displayed a 142% percent increase in plants grown under LED vs. HPS with average photon flux densities of 795 and 298 µmol∙m−2∙s−1 for LED and HPS, respectively. All cultivars of Cannabis sativa L. showed increased cannabinoid potency when grown under LED illumination. The results of this study provide further insight regarding the selection of supplemental light to achieve maximum productivity of Cannabis sativa..."
LED vs. HPS Effects On THC-a
I never had the luxury of keeping my 1kW MH light _four_ feet from the canopy in my 2x5 closet. And in the tents downstairs, depending on what I'm trying to accomplish, I put my LEDs two to three inches away from the top of the canopy during flowering but sometimes 3 plus feet away in veg, to encourage stretch/height.
Here's the take away from the study:
"...at the suggested distance from bulb to canopy in the HPS versus LED comparison (6 inches for LEDs and 4 ft for HPS), carbon assimilation rates displayed a 142% percent increase in plants grown under LED vs. HPS with average photon flux densities of 795 and 298 µmol∙m−2∙s−1 for LED and HPS, respectively. All cultivars of Cannabis sativa L. showed increased cannabinoid potency when grown under LED illumination. The results of this study provide further insight regarding the selection of supplemental light to achieve maximum productivity of Cannabis sativa..."
LED vs. HPS Effects On THC-a
“In this study, all cannabis cultivars grown under LED lights yielded an increase in THCA% with an average increase of 5.39% (mean of 25.06% THCA under LED versus 19.67% under HPS) (Figure 4). The importance of determining the conditions for optimal photosynthetic performance, maximum potency, designing, and operating a cultivation system that consistently maintains these conditions cannot be understated in the cannabis industry-since the majority of product is sold based on weight and cannabinoid potency.”
Well then, thats something.
I noticed a trend for bottom lighting. It never made sense to me why that would benefit more than side lighting. Side lighting causes plants to open up. I don't see any benefit in using bottom lighting over side Lighting. Bottom lighting isn't good for various reasons.
weedemart
Well-known member
The reasons why LED lights offer more performance/quality is because they are much more efficient and therefore emit less radiant heat.
the more the temperature increases, the more cannabinoids are likely to be degraded.
And the co2, re-read carefully, if I understood correctly they compared the co2 levels between two different light intensities so it is normal that the plant consumes more co2.
the more the temperature increases, the more cannabinoids are likely to be degraded.
And the co2, re-read carefully, if I understood correctly they compared the co2 levels between two different light intensities so it is normal that the plant consumes more co2.
hillbil
Active member
I believe 25% is more like a 20% increase over 19% or so.
CharlesU Farley
Well-known member
Thought of you today when I was down doing the mid-flower trim. I've never quite seen this sharp of a delineation in stem color going from green to purple:
Why that happens, I couldn't begin to guess. But to me, it's pretty evident it's not color, genetics, fertilizer, LED lighting, any other things that people usually attribute it to.
Not with that sharp of a delineation.
As with all things in life, it's probably a combination of all of the above, all occurring in a certain sequence, in a certain time frame, having a varible effect.
With less blowhard Boomer bullshit:
It is what it is.
Ive seen a ton of this over the years. I cant attribute it to a single thing either. Not an indication of a health concern ime unless its 100% purple. This usually comes with chlorosis.
jackspratt61
Active member
That's P guy. The question is why.
ohhhhh yeah...
little-soldier
Active member
I've been a long time HID user and not up to date with the new LED tech. I see a lot of those 6-8 bar white leds around now and was wondering if people are getting the same numbers in terms of yield with LEDs compared to HID. Apparently people can pull 3-4-5 pounds out of a 1000w HPS. Does anyone know if anyone has ever pulled that much with LEDs?
weedemart
Well-known member
it all depend on the efficiency of the fixture. Aim for an efficiency of atleast 2.7 umol/s/w and yes at the same wattage you will yield 25%+ more. bulb emit light in all direction, theres a loss in reflection.leds emit light in one direction.
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little-soldier
Active member
if LEDs are only 1 direction then I guess its logic to use bar LEDs for better coverage. Especially in my case because my 1000w hps covers a 6x6 area. thats the secrets to people who claim to get 4-5lbs per light, lol. notice how they never mention how much area their1000w covers. And its more like 1150w cause they all use DE.
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Rocket Soul
Well-known member
Our best stats are 1200, for 12 plants/720w from a space slightly smaller than 2m2, DIY made led. My buddy managed just less than 900 from a m2, 440w tops, also DIY leds.
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mm4n
Well-known member
If it may be helpful, I recently finished my first "HPS vs LEDs" test.
All from seeds (different phenotypes), with a low production (less than 1g/W) and old technology (BridgeLux), but by looking at the photos and numbers you can get an idea of the difference in density/production under LEDs.
little-soldier
Active member
looks like your side by side were right next to each other so you had a bit of the hps overlapping onto your LED grown pants. If you have found the bud density to be considerably higher with LEDs then i guess that concludes everything but then again if you grew different strains and they were from seeds, theres no way to know if bud density wasnt just genetics
Here is one of the FNF going on 40 days under the HLG Diablo. You can see she is yellowing. I get this only under this LED. I will prob swap this light out for the 800w China bar LED.
little-soldier
Active member
if its only making the leaves a lighter green then i wouldnt worry too much about it unless the leaves turn to a bright yellow/no chlorophil left. My guess is the plants right under the leds are more hungry/eat more than the others. Pretty sure light bars will fix this issue as the light is more spread out and less concentrated in the center
