Best colour for cannabis flower only

[LivingLight]

you could however lose more efficiency because each led is getting hotter. and 2A is at rated maximum current.
on the other hand, would you also suggest running 5000K-only in veg stage?

Exactly, the leds are getting hotter this is to take in consideration, and live less longer.
For the vegetative stage, it depends on your configuration. But if space is not a problem, i would run the full spectrum 2700+5000k at equal intensity for the best balance between branching and photosynthetic efficiency

[unkle_psycho]

So, considering the two options for flowering:

-5000k+2700k both running at 1A --> electrical efficiency : 46.5%
-or 2700k only running at 2A --> electrical efficiency : 41.2%

I think i would go for the full 2700k, as the leds are not losing a lot of efficiency running higher.
I don't think the higher blue light amount with the full spectrum could be really beneficial. It could even be the opposite

Wow, this is a surprise for me...

[unkle_psycho]

For veg its good to have general rules, but right now I'm running a pheno hunt for my coming 3d tests, and it seems every plant is giving different node spacing, and also very plant is reacting differently a little differently to changes of spectrum. I'm focusing on this a lot, because I'm aiming at growing sativa dominant trees. Back in the day when I did SOG with indica dominant clones, I never thought about vegging with my metal halide... it was already perfect.

If I was running a commercial op around a clone, surely I would optimize my veg spectrum to get the node spacing I want, and the flowering spectrum for swellage. General guidelines will always be compromise.

[unkle_psycho]

Oh and 'Living light'

The sulfur plasma really is the most expensive light ever. I think this one was 1500e.
Someone having a serious problem with authority decided if growing weed is illegal, he must defiantly try it. Only problem was the dude was straight edge, and didn't even know anyone who smokes. He grew one crop and ended up just throwing all the weed away.
I was introduced to the dude because he needed some consulting, and for some reason the conversation turned to weed. I said I grow, but just got back from a 12y trip to Asia. Later when I was leaving the dude was like 'Here, try this'...

I've never seen a light that vegs better. Plants can be 2m away, or 15cm away, they always look perfect. Never managed to burn anything with the plasma. Also if you use it in the spring to start your outside plants, there is no adjustment period when you move your plants outside.

If this plasma taught me one thing, its the certainty that leaf burn is a spectrum issue, not a problem of intensity. I put 2 week old seedlings 30cm under the bulb for 2 days, and no problem.

But it weighs so much I cant hang it alone. It has a microwave oven inside, and makes a huge racket... I even read about people being paranoid using this light in apartments, because of the sound.

I'm not surprised Gavita and others reinvented plasma and made it quiet.

[LivingLight]

, because I'm aiming at growing sativa dominant trees. Back in the day when I did SOG with indica dominant clones, I never thought about vegging with my metal halide... it was already perfect.

I'm usually trying to get the optimal grow wether i'm doing indica or sativa, and i prefer to let them express what they are.
Indica are not tall but not small either, with 3000-4000k led spectrum, it's growing with a decent node spacing.
Sativas are tall for sure but imo that's not a reason to change the spectrum. They are just having a longer vegetative stage during flowering initiation. So if i want them to fill in a small space, i'm starting flowering earlier.
What is changing concerning spectrum for me, is that i'm using the growing spectrum a bit longer for sativas, as their vegetative stage is longer during the stretch.

Of course the problem is different when i'm growing in microcabs, but i'm using only indicas in this case.

If this plasma taught me one thing, its the certainty that leaf burn is a spectrum issue, not a problem of intensity. I put 2 week old seedlings 30cm under the bulb for 2 days, and no problem.

You are right, in most cases the spectrum is involved in burning-bleaching troubles.
Most people think their HPS are burning leaves becuz it's too hot, but the reality is the hps' spectrum lack of blue and red, the two colors that runs the violaxanthin cycle and control a big part of the photoprotection process. And this lack of photoprotection make their plants burn at "relatively low" light intensity
And concerning the bleaching under led's panels, it's most of the time induced by very high density of light in the uv-blue region (not really burning, it's another kind of stress). Because people don't understant that most led lights produce a fcking huge light density if you are too close from the source

[tazztone]

And concerning the bleaching under led's panels, it's most of the time induced by very high density of light in the uv-blue region (not really burning, it's another kind of stress). Because people don't understant that most led lights produce a fcking huge light density if you are too close from the source

what do you mean? LEDs don't usually have UV, right?
u mean you get more blue dominant the closer you get to the LED ?

[unkle_psycho]

This guy was saying blue burns more then red because the plant generates more heat when converting it to usable form:

"a blue 450nm photon has an energy of 2.76 electron volts while a red 650nm photon 1.91 electron volts. It takes less energy to generate a red photon so while blue is more electrically efficient, red is more energy efficient.

Also, there's 2 photo systems a photosynthetic reaction center, PS1 ans PSII. It's part of the very important Z scheme. They require 2 photons to complete, one 680nm and one 700nm or an average of about 1.78 electron volts of energy. That red 650nm photon lost 0.18 electron volts due to heat from this mismatch and the blue LED 0.98. Wasted heat. Plant thermodynamics."

And UV has even higher energy...

[unkle_psycho]

So is there a difference in this internal heat vs external heat? Is it somehow that red light sources heat more from the outside, while white sources from the inside??? WTF

[unkle_psycho]

, because I'm aiming at growing sativa dominant trees. Back in the day when I did SOG with indica dominant clones, I never thought about vegging with my metal halide... it was already perfect.

I'm usually trying to get the optimal grow wether i'm doing indica or sativa, and i prefer to let them express what they are.
Indica are not tall but not small either, with 3000-4000k led spectrum, it's growing with a decent node spacing.
Sativas are tall for sure but imo that's not a reason to change the spectrum. They are just having a longer vegetative stage during flowering initiation. So if i want them to fill in a small space, i'm starting flowering earlier.
What is changing concerning spectrum for me, is that i'm using the growing spectrum a bit longer for sativas, as their vegetative stage is longer during the stretch.

Of course the problem is different when i'm growing in microcabs, but i'm using only indicas in this case.

If this plasma taught me one thing, its the certainty that leaf burn is a spectrum issue, not a problem of intensity. I put 2 week old seedlings 30cm under the bulb for 2 days, and no problem.

You are right, in most cases the spectrum is involved in burning-bleaching troubles.
Most people think their HPS are burning leaves becuz it's too hot, but the reality is the hps' spectrum lack of blue and red, the two colors that runs the violaxanthin cycle and control a big part of the photoprotection process. And this lack of photoprotection make their plants burn at "relatively low" light intensity
And concerning the bleaching under led's panels, it's most of the time induced by very high density of light in the uv-blue region (not really burning, it's another kind of stress). Because people don't understant that most led lights produce a fcking huge light density if you are too close from the source

But in my current mixed run, I used plasma for the first two weeks of veg, then used HID for about ten days and swiched back to plasma. I also did the first month of flowering under the plasma, because I'm living as someones guest, and even a 1/1000000 chance of burning their house down is unacceptable. Now weather warmed up so I'm doing the rest of the flower under 2 400w HIDs from the 90's.

Since the plants are quite tall, I can see the node spacing under both spectrums, I want to write all the numbers down, but they seem to have pretty individual responses to everything. Even the ones that are the same strain. Theres a g13/haze that grew short and bushy under both lights, then another which had pretty uniform node spacing, maybe double space and double size plant, but little side branching. The third one streched 50cm even under plasma, and had at least 15cm node spacing under the HID.

So my impression really is that to optimize the node spacing I need to work with clones, and have a light recipe and placing strategy which is individualized.

[LivingLight]

And concerning the bleaching under led's panels, it's most of the time induced by very high density of light in the uv-blue region (not really burning, it's another kind of stress). Because people don't understant that most led lights produce a fcking huge light density if you are too close from the source

what do you mean? LEDs don't usually have UV, right?
u mean you get more blue dominant the closer you get to the LED ?

i've seen uv leds on most of the bleaching cases. At a point it wasn't rare to find some uv in blackdog panels or some other crap.
Nowadays it's rare to see uv leds, but people keep buying led lamps with a high amount of blue light like 4000 and 5000k led spectrums. This is way more aggressive than a warm white and lead easily to some kind of bleaching.
I see it clearly on a friend's setup who share strains with me. He is using 4000k and keep his light a bit close to the canopy, this often leads to a pigment's degradation on the higher leaves and a very slow development.
Growing the same strains under 3000k, i got no problem even getting higher light density, i can keep the cobs at 10cm of the top canopy when my friend got problems at 20cm.

It's not a problem of spectrum changes with distance to the leds, i don't know where you get this idea xD
just a problem of high density of light with aggressive wavelenght