Grow light color spectrum question

[Bradyrollie4]

So I have these lights I am experimenting with. They have the option to turn on just red, white, or blue. Or run them all simultaneously Or vise versa. I can also mix them (example: red/blue, blue/white. They work amazing when I veg with blue/red. Full spectrum. Or even just blue. But if I flip to flower, what will happen if I use just red? Red/blue? Red/white? Anyone have any experience in this area?

 

[LoveGrowingIt]

I only have full-spectrum lights. That said, my understanding is blue light is for vegetation and red light is for flowering. That's based on how plants evolved and adapted to seasonal changes of sunlight, which is bluer when the sun is higher in the sky during the summer and redder when the sun is lower during the fall.

 

[Eledin]

I would run them all simultaneously to get a "full spectrum" or as close as possible. While what @LoveGrowingIt says its true, it doesnt mean they only have red light, they still have plenty of blue light during flower just less. The more expensive panels will use cool white, warm white and red leds to give a full spectrum. Cool white gives a a lot of blue and some red, warm blue gives more or less the same red as white depending on the Kelvins. Runing only blue lights and only red lights for veg and flower will make them miss a lot of the spectrum that they would have with the sun and practically nobody does that anymore, full spectrum is always better. You will notice that bluerples how theyre called (blue+red leds) are cheaper and thats for a reason, theyre missing colors in the spectrum like yellow, green, cyan (all of which you can get with white LEDs) and if we wanna get picky infrared and UV chips too. White LEDs are also more energy efficient than blue LEDs.

 

[Eledin]

That said you can still grow pretty good weed with them Im not saying they completely suck, Im saying people have moved on from them as white LEDs reinforced with red are much better. You can still grow killer weed, Ive used them and I still have them saved in case of need but I also moved on to white LEDs.

 

[Eledin]

This is a good article and while its not focused on weed the same happens with weed and I have experienced it, less production and more stretching of the main branch (but not the others) with blurples. It also leads to another article explaining why green light is important as oposed to what was thought before (tl;dr: it was thought that plants did not use much green spectrum because is the color they reflect the most, hence why they appear green to us, but they actually only reflect 5% or so of green and the rest is put to use).

What is PAR Light? (Photosynthetically Active Radiation): Spectral Quality of Horticultural Lamps & LEDs -AlboPepper.com

Good quality PAR light is crucial for healthy plant development. Don't prescribe to the mentality that plants only need one or two colors!

albopepper.com

Big take away from the article. Blurple spectrum vs full spectrum with white LEDs, you can see the absence of cyan, green and yellow with blurples:

 

[Eledin]

I missed that you say they have some white LED aswell? Good, run them all Id say! Focusing on mostly blue and mostly red during veg and flower is not good so those white LEDs will come in handy. It would be better if they all were white, with some warm white aswell and a few reds, but its still pretty good if you run them all.

 

[One_Bell]

I am using full spectrumm led's ( Samsung LM301H Evo's) And use additional blue light in veg, and deep red (with UV and IR) during flower.

 

[LoveGrowingIt]

While what @LoveGrowingIt says its true, it doesnt mean they only have red light, they still have plenty of blue light during flower just less.

Sorry if my meaning was unclear. I wasn't suggesting only one color be used. The post was only intended to briefly describe the evolutionary adaptations that result from changing angles of the sun as seasons change, and how those changing angles affect the solar spectrum relative to the life stages of the plants.

Here's some more information:

Blue-Heavy light (appears white or bluish) – Grow lights with a higher ratio of blue light are often used in the vegetative stage as they tend to make cannabis plants grow short and squat, with big healthy leaves. Blue-heavy light tends to keep cannabis plants shorter and bushier in the vegetative stage, but reduces yields if used in the flowering stage. Blue-heavy light typically appears white or tinged with blue.

Red-Heavy light (appears red, yellow, or pink) – Grow lights with higher amounts of red are often used in the flowering stage to encourage plants to grow tall (stretch) and to help promote budding, resulting in bigger yields for the amount of electricity used. Plants may also switch to the flowering stage faster under red-heavy light than under blue-heavy light.

Source: https://www.growweedeasy.com/color-spectrum-marijuana-grow-light

 

[Eledin]

Sorry if my meaning was unclear. I wasn't suggesting only one color be used. The post was only intended to briefly describe the evolutionary adaptations that result from changing angles of the sun as seasons change, and how those changing angles affect the solar spectrum relative to the life stages of the plants.

Here's some more information:


Source: https://www.growweedeasy.com/color-spectrum-marijuana-grow-light

Sorry if I came across like I was trying to correct you I wasnt, I was just using part of what you said as an example of while its true, that doesnt mean that using only or predominantly one color is a good reflection of the spectrum of the sun even in winter when it has more red and less blue. The science behind more blue in veg and more red in flower is true but still a full spectrum non specialized LED will work better due to the lack of a wide spectrum in blue and red LEDs thats what I was trying to say. Red LEDs are always nice to have but without warm white and cool white theyre kinda shitty not gonna lie hahaha theyre only good to reinforce the red, specially for flower, but warm white has plenty of red for flower too. If I had to choose a panel for veg and another for flower, I would have into consideration how much blue and red they have but they would still be cool and warm whites reinforced with red, just balanced differently. The flowering panel would have more warm white and less cool white than the veg panel. Or it could use only warm white, which is very balanced in blue and red perfect for flower and mimics much better the full spectrum of the sun in winter than just red, red and blues, purple or pink.

 

[Bradyrollie4]

I am using full spectrumm led's ( Samsung LM301H Evo's) And use additional blue light in veg, and deep red (with UV and IR) during flower.

So I been running just blue during veg, and damn they exploded faster then normal. I been playing around with the same strain for months now. My AC Evo 10 is my flower light, but I’m setting up a trellis tent in my 4x4 where this light is and am really curious when I flip to flower what happens if I do straight red or red/white what results I would get. Or even red/blue.

 

[One_Bell]

So I been running just blue during veg, and damn they exploded faster then normal. I been playing around with the same strain for months now. My AC Evo 10 is my flower light, but I’m setting up a trellis tent in my 4x4 where this light is and am really curious when I flip to flower what happens if I do straight red or red/white what results I would get. Or even red/blue.

Please try and let us know. My plants also experienced vigirous growth when adding the blue light. Currently struggling a bit in mid/late flower, so I can't tell what the other lights do.

 

[Eledin]

So I been running just blue during veg, and damn they exploded faster then normal. I been playing around with the same strain for months now. My AC Evo 10 is my flower light, but I’m setting up a trellis tent in my 4x4 where this light is and am really curious when I flip to flower what happens if I do straight red or red/white what results I would get. Or even red/blue.

By they exploded you mean they stretched more? Because thats not desirable and thats precisely why I use full spectrum, so they dont get as tall and they get more bushy. That said if you like tall plants there's nothing wrong with it but using just blue is gonna make them stretch more, meaning the lower buds will get less light. Ive already been through blues, reds and even pink and theyre long packed inside a box but thats just my experience.

 

[One_Bell]

By they exploded you mean they stretched more? Because thats not desirable and thats precisely why I use full spectrum, so they dont get as tall and they get more bushy. That said if you like tall plants there's nothing wrong with it but using just blue is gonna make them stretch more, meaning the lower buds will get less light. Ive already been through blues, reds and even pink and theyre long packed inside a box but thats just my experience.

You are not asking me, but the blue light gave more growth which I bended horizontal to evenout the canopy. If you look at my growdiary you can see them getting more bushy instead of stretching. Tight internode spacing someone else mentioned.

 

[Eledin]

All of the big LED brands for cannabis growing have long swaped to cool and warm white too. You wont find a high end LED that uses blue, or even a cheapest model from the known brands. Again, there's a reason why blurples and blues are so cheap compared to a full spectrum panel... people have moved on, theyre not good. With just blue your plant is gonna grow more yes but it wont grow bushy, you will have a very tall plant with a lot of internodal space because youre missing the whole light spectrum but blue.

 

[Eledin]

You are not asking me, but the blue light gave more growth which I bended horizontal to evenout the canopy. If you look at my growdiary you can see them getting more bushy instead of stretching.

I will check right now, but Im very skeptycal as like I just said everyone moved on from blues and blurple, is not a new thing, its old and in the past.

 

[Eledin]

Well youre not using just blue light like the person I answered to, youre adding blue to cool white as far as I can see.

 

[One_Bell]

I will check right now, but Im very skeptycal as like I just said everyone moved on from blues and blurple, is not a new thing, its old and in the past.

Unfortunately I can't comment on that since it is my first grow and can't compare it to anything else.

 

[One_Bell]

Well youre not using just blue light like the person I answered to, youre adding blue to cool white as far as I can see.

Yeah that is true, I using it as an additional light to the mainlightning (Samsung lm301h evo).

 

[Eledin]

Yeah that is true, I using it as an additional light to the mainlightning (Samsung lm301h evo).

Thats a good full spectrum panel. Cool white has more blue than red already but adding even more blue might have helped growth? I have tried blurples but never added blue to cool white as it already has a blue to red ratio similar to the sun for veg. But yes if its your first grow its hard to know if it really made a difference.

 

[Eledin]

I can see that your panel has the same blue as red, in most cases there's slightly more blue than red. I can see your plants benefiting from blue light with that exact panel.