LED and BUD QUALITY

[Prawn Connery]

Why bring up that expression and then reference nasas blurple light if you arent indicating hes unaware? I understand the inconsistencies you may have found with some of his studies regarding high thc cannbis. Id like more details on those if you have them besides this 3 plant study(who did that study and where is that info from?). Id also love to see that same experiment with more than one cbd plant, weve certainly seen how different strains of drug type cannabis behave very differently. Ive been growing high thc cannabis for over 20 years. I still have had many ah ha moments and realizations through his very detailed courses with royal heins and mitch wesmoreland. His light meter was an extremely helpful tool so im glad i bought what hes selling there. They do have a meter for UV-A https://www.apogeeinstruments.com/uv/

And im just curious, are you also a salesman? Iirc correctly you do sell Led lighting, do they happen to feature UV diodes?

Just saying you can have all the tools of modern science, but you might come to the wrong conclusions if you go down the wrong paths to begin with.

There's a link to the study right before my post.: https://www.icmag.com/threads/led-and-bud-quality.18123147/post-18514680

I was talking about a PAR meter that has full sensitivity into the UVA range.

I design LED grow lights yes, am affiliated with Grow Lights Australia, and we have 405nm diodes in our spectrum that bleeds into the UVA range. There is 1% UVA in them. You could consider me a salesman, although I do not personally sell anything.

 

[weedemart]

uv/blue photon are really usefull photon to

1. reduce stretch
2. cause positive stress, if well timed
3.increase overall photoactivity effiency.

thing is you dont want too much blue and very little uv, as someone pointed out.


If you running a commercial facility, it doesnt really matter.

Thing is led grow light has to be very efficient to be worth the investment. DE HPS achieve 2.1umols/w

Bugbee said it, effiency is more important than spectrum. So wtv spectrum, if you go with led take the most efficient.

The only pro i see from led is reducing the heat load thats why effiency is the only thing that matter.

Best led at moment is 2.7umol/w. so only 33% more efficient for more than double the cost of equivalent DE hps

 

[jayr1787]

I grew this one under a mars hydro FCE-6500 autoflower from fastbuds, gorilla cookies. she's still hanging.

 

[zachrockbadenof]

View attachment 18945669 View attachment 18945670 View attachment 18945671 View attachment 18945672 I grew this one under a mars hydro FCE-6500 autoflower from fastbuds, gorilla cookies. she's still hanging.

it sure looks mighty nice...

 

[jayr1787]

Has some serious chemdawg smells and is really potent. I grew 2 of these plants the other plant gave me like 508 grams dried. Definitely strong smelly autoflowers. I'm impressed. I grew 2 gorilla cookies 2 cherry colas 2 strawberry gorillas and 2 ztrawberriez and ended up with 5.4 lbs and still have that one plant hanging upstairs to weigh out. Fastbuds was the Breeder. Grown in a 4x8 raised bed indoors and then the other 3 were in the 4x4 tent under the mars hydro.

 

[Crooked8]

Just saying you can have all the tools of modern science, but you might come to the wrong conclusions if you go down the wrong paths to begin with.

There's a link to the study right before my post.: https://www.icmag.com/threads/led-and-bud-quality.18123147/post-18514680

I was talking about a PAR meter that has full sensitivity into the UVA range.

I design LED grow lights yes, am affiliated with Grow Lights Australia, and we have 405nm diodes in our spectrum that bleeds into the UVA range. There is 1% UVA in them. You could consider me a salesman, although I do not personally sell anything.

Thanks for the link! Its also interesting that this is also showing the major differences only after they push the lighting to more than 12/12.

 

[HarleyJammer]

All I want to know is under LED should I expect Mag or Boron deficiency .. and stay away from Calcium Carbonate.

 

[Crooked8]

All I want to know is under LED should I expect Mag or Boron deficiency .. and stay away from Calcium Carbonate.

No, just measure your light. Increase overall feed in accordance with your increase in photons.

 

[Prawn Connery]

All I want to know is under LED should I expect Mag or Boron deficiency .. and stay away from Calcium Carbonate.

You generally need a higher EC under LED due to less transpiration. Remember that most nutrient formulas on the market today were designed to feed HID (HPS, CMH) plants. LEDs run cooler, so there is less evaporation at the root zone (pot dries out slower) and less transpiration from the leaves, which slows uptake of nutrients, especially calcium and magnesium.

HID nutrient formulas assume X amount of light for Y amount of radiated heat (ratio of PAR to IR), so are balanced to work under lights that have higher transpiration rates.

Most coco nutrients have elevated levels of Ca and Mg in them to offset coco's propensity to cation exchange Ca and Mg for Na and K. If you have a good, well-balanced nutrient with higher levels of Ca and Mg, simply increasing the EC should suffice.

I do use a Ca/Mg supplement, but mine is a mix of calcium-nitrate and magnesium-nitrate, so has added nitrogen as well as boron.

I use this: https://professorsnutrients.com.au/products/go-green/

I need to add a caveat: I use flowering nutrients all the way through, including during veg. I use Go Green as a nitrogen as well as calcium and magnesium supplement, but I also use it in the first few weeks of flowering, during the stretch, as that is when the plant has high N, Ca and Mg demands as it has a very fast rate of stem, leaf and bud-site growth and development before the onset of flowering.

PK (K) can lock out Ca and so it is not uncommon to see calcium deficiencies in plants that have been hit hard or too early with PK.

 

[Prawn Connery]

Thanks for the link! Its also interesting that this is also showing the major differences only after they push the lighting to more than 12/12.

My initial thoughts on the results are that cannabinoid production (at least THC) peaks about 2-3 weeks before we traditionally harvest. This appears to align with what happens in nature during the flowering cycle when UV levels are higher early on during peak production of secondary metabolites, but reduces as the sun gets lower on the horizon during autumn (or during axis tilt on the equator).

So it would make sense that you want UV levels slightly higher during peak cannabinoid production, but to reduce it after this so that high UV does not photo-oxidise cannabinoids as production (replacement rate) slows.

When you change the light schedule by increasing it towards the end of flowering, you are actually providing more oxidative photons at a time when, instead of stressing the plant into producing higher rates of secondary metabolites, peak metabolite production has passed, and so the extra photon energy starts to oxidise cannabinoids instead of promoting them.

As to why CBD goes up but THC goes down, it's hard to tell from the study as they didn't publish CBGA results so we don't know if the extra photonic energy is synthesising CBGA into more CBDA and less THCA, or if THCA oxidises more readily into CBN than CBD.

 

[CocoNut 420]

the study is from australia, and the video linked from usa does a similar study with similar results but focused more on bud ripeness and quality

Moving Away from 12:12; the Effect of Different Photoperiods on Biomass Yield and Cannabinoids in Medicinal Cannabis

The standard practice to initiate flowering in medicinal cannabis involves reducing the photoperiod from a long-day period to an equal duration cycle of 12 h light (12L)/12 h dark (12D). This method reflects the short-day flowering dependence of many cannabis varieties but may not be optimal for...

www.mdpi.com

That was very interesting, tbh I expected more light would = better, full stop.

After it's explained it seems logical, I was thinking about trying 13/11 but I don't think I'll bother with that now.

Thanks for sharing!

 

[greyfader]

All I want to know is under LED should I expect Mag or Boron deficiency .. and stay away from Calcium Carbonate.

i run 900 ppm or ec 1.8 with 1200 ppfd. depending on the nutrient brand you may have to add magnesium sulphate but not calcium.

 

[HarleyJammer]

You generally need a higher EC under LED due to less transpiration. Remember that most nutrient formulas on the market today were designed to feed HID (HPS, CMH) plants. LEDs run cooler, so there is less evaporation at the root zone (pot dries out slower) and less transpiration from the leaves, which slows uptake of nutrients, especially calcium and magnesium.

HID nutrient formulas assume X amount of light for Y amount of radiated heat (ratio of PAR to IR), so are balanced to work under lights that have higher transpiration rates.

Most coco nutrients have elevated levels of Ca and Mg in them to offset coco's propensity to cation exchange Ca and Mg for Na and K. If you have a good, well-balanced nutrient with higher levels of Ca and Mg, simply increasing the EC should suffice.

I do use a Ca/Mg supplement, but mine is a mix of calcium-nitrate and magnesium-nitrate, so has added nitrogen as well as boron.

I use this: https://professorsnutrients.com.au/products/go-green/

I need to add a caveat: I use flowering nutrients all the way through, including during veg. I use Go Green as a nitrogen as well as calcium and magnesium supplement, but I also use it in the first few weeks of flowering, during the stretch, as that is when the plant has high N, Ca and Mg demands as it has a very fast rate of stem, leaf and bud-site growth and development before the onset of flowering.

PK (K) can lock out Ca and so it is not uncommon to see calcium deficiencies in plants that have been hit hard or too early with PK.

Thanks, Prawn. I'm coming back into the hobby from T8/HPS/outdoor and trying out full spectrum LED on a new grow. I have noticed there is a slight learning curve from HPS to LED (behavior & biochem). Again, thank you for your informative reply. People like you make IC great.

 

[HarleyJammer]

i run 900 ppm or ec 1.8 with 1200 ppfd. depending on the nutrient brand you may have to add magnesium sulphate but not calcium.

Hi Grey. I will run a little 300w LED in a 3x3 tent. I dont think it will get over 900 ppfd. I am planning on using a well draining soil. I have always used Epsom salts in a foliar feed application for mag/sulphur. It seems I might have to bump up dosage/frequency but I'll see what the girls say when they get into the tent next week.

 

[weedemart]

the best light cycle is the one that is closest to the nature in which cannabis has adapted for hundreds of years. Pushing the cycles to extremes will only cause stress to the plant. 18/12 in veg is optimized for an indoor environment (lower light than outside) but a cycle of 16-8 would do very well too. The factor determining the rate of growth is not the length of the day but rather the volume of photons that the plant receives during a day. Cannabis thrives between 35-45 moles per day. The thing to remember is that the shorter the days, the more light must be intense to achieve the same result of photosynthesis. The limit then struck by shortening the lighting times but by increasing the intensity is that the needs of the plants also increase up to the saturation point (co2 , fertilizer etc...) so theres no point trying to experiment on this topic ,whatever solution you will end up with, you will end up with the same limitation and even worst end product.

 

[weedemart]

I will be clearer, the previous research published in this post is insignificant because the author of the research did not take the time to adjust the ppfd according to the lighting time. so yes according to its results, in 10L/14 the weight of the harvest decreased but it is normal the plants received 20% fewer photons per day. And this applies to veg too. cannabis saturates around 2000 umol/s and at this intensity you need not only enrichment with co2 but an ideal climate/feed to avoid damaging the plant.

There is a direct correlation between photon intensity and fertilization. Furthermore, when we increase the photon intensity, we will hit the saturation point. At this time, photosynthesis is limited by CO2. if we push the CO2, then we can take advantage of the increase in photons. And if we decide to take this route, we will have to increase the fertilization dose. However, all true connoisseurs know that overfertilizing cannabis is not the best quality.


In short, those who irradiate their plant at more than 1000 umols/s don't understand anything.And same for those who try to play with rules of the legacy market,who started over 3 decade ago. Playing with hours of light without applying the science behind it and claiming ''oh the 12/12 light cycle is a myth'',just show how clueless people are.

Sorry guys.


Funny part of this story is... those guys are probly PhD. The legal cannabis industry are bunch of clowns, keep flushing your money down the drain.

 

[phunkeeboodah]

That was very interesting, tbh I expected more light would = better, full stop.

After it's explained it seems logical, I was thinking about trying 13/11 but I don't think I'll bother with that now.

Thanks for sharing!

the studies compliment each other so to me that is enough to try at least once

the first study (usa - video link) does not look at changing the photoperiod during flower, just fixed photoperiods of different lengths, EXCEPT as an aside, where they found with og, if they bumped the second half of flowering back up to 12/12 from 10/12 they would see an increase in overall yield but without losing the added quality that 10/12 brought

it really just showed how some high thc varieties will produce a frostier, more ripe, more quality bud when flowered at lower than 12/12 straight through, in this case 10/14

they incidentally filled in the gaps of the other study (aus - paper link) by corroborating that they could greatly increase weight and thc in some (not all, yet to no ill effect otherwise) high thc varieties by changing the flowering period in the same way half way through

the aus study just showed what happens when a change is made half way through, along with controls for straight through. they didn't hone in on the higher bud quality aspect of just reducing flowering daylight hours like the other study, and they used the times 10L/14D, 12L/12D and 14L/10D and all combinations thereof in either short/long, long/short and fixed

looking at both studies, that yield increase trick for high thc varieties is corroborated and can occur at beginning or end of flower i.e. the short daylight hours acan occur first and then switch to longer, or vice versa like in nature

to me it all seems to say the ideal way to potentially greatly increase yeild in a high thc variety is porbably best done by mimicking nature, so instead of 12/12 for the first half of flowering and 14/10 for the second (or vice versa). so i would just gradually lower the daylihgt ours every week or two (ideally we casn get a program to run with a timer than can do it exactly like nature maybe they should start making them)

and with that first study added in again there can be some experimentation in lowering the daylight hours below 12/12 at some point as they found this speeds up the ripening and makes a frostier better quality bud at the expense of yeild (though with quicker ripening this is mitigated a bit)

 

[weedemart]

the studies compliment each other so to me that is enough to try at least once

the first study (usa - video link) does not look at changing the photoperiod during flower, just fixed photoperiods of different lengths, EXCEPT as an aside, where they found with og, if they bumped the second half of flowering back up to 12/12 from 10/12 they would see an increase in overall yield but without losing the added quality that 10/12 brought

it really just showed how some high thc varieties will produce a frostier, more ripe, more quality bud when flowered at lower than 12/12 straight through, in this case 10/14

they incidentally filled in the gaps of the other study (aus - paper link) by corroborating that they could greatly increase weight and thc in some (not all, yet to no ill effect otherwise) high thc varieties by changing the flowering period in the same way half way through

the aus study just showed what happens when a change is made half way through, along with controls for straight through. they didn't hone in on the higher bud quality aspect of just reducing flowering daylight hours like the other study, and they used the times 10L/14D, 12L/12D and 14L/10D and all combinations thereof in either short/long, long/short and fixed

looking at both studies, that yield increase trick for high thc varieties is corroborated and can occur at beginning or end of flower i.e. the short daylight hours acan occur first and then switch to longer, or vice versa like in nature

to me it all seems to say the ideal way to potentially greatly increase yeild in a high thc variety is porbably best done by mimicking nature, so instead of 12/12 for the first half of flowering and 10/14 for the second. so i would just gradually lower the daylihgt ours every week or two (ideally we casn get a program to run with a timer than can do it exactly like nature maybe they should start making them)

and with that first study added in again there can be some experimentation in lowering the daylight hours below 12/12 at some point as they found this speeds up the ripening and makes a frostier better quality bud at the expense of yeild (though with quicker ripening this is mitigated a bit)

This is all non sense. Plant doesnt sense time the way we do.

 

[phunkeeboodah]

i am ignorant of actual facts and scientific method/study and also i enjoy shoving my headup my own butt : )

 

[phunkeeboodah]

the ignorance is hilarious bro seriously lol