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LED and BUD QUALITY
- Thread starter Tropical Sun
- Start date
exoticrobotic
Well-known member
Cerathule
Well-known member
While all of this is true, let me just tell you that there are several independant mechanisms to stomatal conductance and one such is the very presence of photosynthesis done. As guardcells do contain chloroplasts. That is, any PAR light (regardless of spectrum) will open the stomatas and this is the very reason why most - if not all - studies on stomatal conductance (in response to spectrum) use a very low background fluence and extremely short flashes of light to do away with this (photosynthesis).This article also helped me understand a lot about Temp differences and how plants respond to a light.
InSpire Blog | Does Light Spectrum Alter Plant Transpiration Rates?
Disclaimer: This article originally appeared in the September 2021 issue of Cannabis Science & Technology.inspire.ag
Plants grown under LED fixtures are exposed to virtually zero direct infrared radiation, which is a novel experience compared to the conditions they are typically accustomed to in nature. HPS lamps emit quite a bit of infrared radiation, which is why they get so hot and why you can feel a warming effect when you are underneath them. As mentioned in our first article in this series, infrared will heat the water inside of a plant, causing it to transpire at a faster rate due to the intense warming effect on the vapor in the leaves. However, HPS lamps do not emit much blue light (around 3%), which is what separates them from sunlight and LED fixtures. Blue light induces stomatal opening in the plant. Sunlight emits a large amount of infrared, but the huge quantity of blue light signals the plants to stay cool. We could say that because HPS lamps lack this light fraction, the temperature in most grow rooms needs to be kept milder at around 24-25°C (75-77°F) to account for an increased thermal load from the lamp and a decreased signaling capacity. The temperature of the canopy is far more important than the temperature of the air, particularly when the lights are on.
LEDs have a high fraction of blue light, which induces stomata to stay open. However, since this is paired with almost zero infrared, the plants stay very cool and room temperature needs to be kept much higher at 27-30°C (80-86°F). To make things even more complex, green light reverses the stomatal opening effect of blue light. More research is needed in order for us to fully understand how this impacts transpiration directly and how this differs in the presence of infrared light, but it certainly seems that this is a contributing factor to the temperature tolerance differences we see in HPS and LED grow rooms.
In other words all the photons emitted by a HPS lamp (excluding some of the Far-Red -the turning point is somewhere around 715-720nm- and fully including IR) will open the stomatas. However, studies have shown that under a blue-enriched spectrum the stomatas open a tad more, but this is weak evidence in relation to leaf surface temperature or waterloss. It mostly affects gas exchange which in turn affects intraleaf CO2 levels and hence photosynthesis rate.
The evapotranspiration under HPS is bigger than under LED, regardless of its diminished bluelight impulse. This is because when leaves are warm the water has more energy to make it into the gaseous phase. This seems to be a much bigger factor than a few % back or forth of stomatal conductance.
62 pages..62pages of BS... not all BS for sure, but there was a bit.... why not just grow outdoors under that big hps/mh/led/cmh in the sky... there is no better light source....
Corpselover Fat
Active member
I live in the city and I want decent bud. Haven't really had any decent outdoor bud here. I'm sure some manage to grow ok or even good outdoor bud, but I haven't had any.
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exoticrobotic
Well-known member
I wish i could grow outdoors under the sun, it's the best way but it's much more effort and much riskier than growing indoors.
One day the UK will catch up with the rest of the world and i'll try a small field outdoors.
I hear Rishi's mates already have large grows going.
and of course u need to grow indoors under a lig
i have been in the uk probably 50times...LUV IT.... but u guys can sell the seeds... u just can't grow em... weird laws... and not just in the uk...
exoticrobotic
Well-known member
it's also legal for med purposes in the uk if you can prove you have a condition that has not been managed effectively by the national health service at least 2 times.
but still not legal if you have such a condition and want to grow your own medicine.
but still not legal if you have such a condition and want to grow your own medicine.
Corpselover Fat
Active member
If I lived somewhere where I could setup a greenhouse I would try it. Using the sun would be infinitely more electrically efficient than even the best leds and I would love it if my cannabis didn't require the use of electricity. The growing season up here is short and you really need to grow auto strains due to the long days. Some fast strains can be grown outside too, but the season is still short.
The purple kush they grew outdoor here a few years back (med ops) was insane, two hits and your gone
Most of the med weed was growing outdoor here, and it was mostly killer with PK as the king, all others were very good smoke with all the effects tastes and differences.
You could actually know what you are smoking, today they all smell kinda the same, shoe box soap chemical cleaner something like that and have the same potency, it became such a "avg" product it's just not worth buying anymore.
I truly wonder whats gone wrong, cuz med ops still grow outdoors here, but the private mass outdoor growers bud is better
Everything is a mess.
Most of the med weed was growing outdoor here, and it was mostly killer with PK as the king, all others were very good smoke with all the effects tastes and differences.
You could actually know what you are smoking, today they all smell kinda the same, shoe box soap chemical cleaner something like that and have the same potency, it became such a "avg" product it's just not worth buying anymore.
I truly wonder whats gone wrong, cuz med ops still grow outdoors here, but the private mass outdoor growers bud is better
Everything is a mess.
Thanks, for your input. Not much different from the link I posted. Do you have any published sources?
@Crooked8 I just now saw you edited your post, the height is 70 cm I think, the heat is just too much in this time of year here to take it any lower
I know I might miss a lot of parameters when I work at this temps, density, colors, stress
But I'm just looking for something to smoke
The smoke is the only parameter we care about now, not yield, not density not anything, we are so discouraged by the mids all around that we don't care anymore about everything else
When I get that dope dank smoke I can assure you the next runs is gonna be perfect
I know I might miss a lot of parameters when I work at this temps, density, colors, stress
But I'm just looking for something to smoke
The smoke is the only parameter we care about now, not yield, not density not anything, we are so discouraged by the mids all around that we don't care anymore about everything else
When I get that dope dank smoke I can assure you the next runs is gonna be perfect
@exoticrobotic You said you had “yet to see it”. Well, youve seen it, id actually love to see these headless trichomes you hps lovers speak of plaguing the led industry. Ive tried 6 different fixture brands and none of them produced product like snake and you have mentioned.
Hate to say it but boy would an led reduce that heat for the same ppfd hahaha@Crooked8 I just now saw you edited your post, the height is 70 cm I think, the heat is just too much in this time of year here to take it any lower
I know I might miss a lot of parameters when I work at this temps, density, colors, stress
But I'm just looking for something to smoke
The smoke is the only parameter we care about now, not yield, not density not anything, we are so discouraged by the mids all around that we don't care anymore about everything else
When I get that dope dank smoke I can assure you the next runs is gonna be perfect
. You would likely drop those temps to a very respectable range. I understand your opposition, but this is an ideal example of when an Led fixture would be a huge benefit.Oh yes I know, and I would love to apply some in my veg tent mainly, I sacrifice heat for those hps no doubt, but that's the flower tent, can't put LEDs there, for me it's like betrayal 
Those are just a couple, there's so much more from so much more breeders or growers..
I doubt that was grown under HIDs...
But maybe it's just genetics ? I dunno.
Wait a sec...
Those are just a couple, there's so much more from so much more breeders or growers..
I doubt that was grown under HIDs...
But maybe it's just genetics ? I dunno.
fuk me..... nice looking bud....big thumbs upOh yes I know, and I would love to apply some in my veg tent mainly, I sacrifice heat for those hps no doubt, but that's the flower tent, can't put LEDs there, for me it's like betrayal
Wait a sec...
View attachment 18842548
View attachment 18842549
View attachment 18842550
Those are just a couple, there's so much more from so much more breeders or growers..
I doubt that was grown under HIDs...
But maybe it's just genetics ? I dunno.
Corpselover Fat
Active member
Those are breeder pics, which he posted as examples of headless trichomes. Looks to me like what produces headless trichs is low resolution and what looks like image artefacts due to processing.
if colors could get u high......
In the first two photos i see plenty of trichome heads. This indicates it was likely damaged during processing. The last one just looks like it was tumbled or something. But unless you can prove they were cultivated under leds and werent mishandled your theory goes out the window completely regarding leds producing trichomes with no heads. Nothing about those pics is conclusive. I wouldnt be surprised if those buds came from hps.Oh yes I know, and I would love to apply some in my veg tent mainly, I sacrifice heat for those hps no doubt, but that's the flower tent, can't put LEDs there, for me it's like betrayal
Wait a sec...
View attachment 18842548
View attachment 18842549
View attachment 18842550
Those are just a couple, there's so much more from so much more breeders or growers..
I doubt that was grown under HIDs...
But maybe it's just genetics ? I dunno.
Yeah it has heads, but more neck then heads, and very very small head, mostly just stalk.
That's just weird, the last one could've been tumbled or some I don't know
I just know I see plenty like this, and most are still on the plant, not processed
So we can supply hundreds of pics and examples but it will never be conclusive from them there's no point to put them to much, the phenomena is real, it's not fiction, studies say it and our eyes and smoke say it
But, not conclusive indeed, Im not putting my foot down until I do a side by side with same clone under a led you, Crooked8, will pick.
That's just weird, the last one could've been tumbled or some I don't know
I just know I see plenty like this, and most are still on the plant, not processed
So we can supply hundreds of pics and examples but it will never be conclusive from them there's no point to put them to much, the phenomena is real, it's not fiction, studies say it and our eyes and smoke say it
But, not conclusive indeed, Im not putting my foot down until I do a side by side with same clone under a led you, Crooked8, will pick.
