What is the importance of far red light?....

[shaggyballs]

I added far red to my LED setup this grow. They come on 5 minutes before main lights and turn off 15 minutes after main. Plants from seed showed sex in 5 days, running a 13on/11off light cycle. The plants are very narrow leaf type, but extra stretch hasn't been a major factor with the addition of the far red (730nm).

Thank you for sharing that info.
I was trying to suggest that stretch should not be a factor to Horselover Fat but I had no real life example to give.

You can add more far red but you need to maintain the ratio between red and far red to reduce stretch.

So you hear that folks far red does not have to equal stretch.

I miss Beta, he did drop some good knowledge before he left.

 

[Horselover Fat]

Both red and far red elongate plants. I'm not saying a bit of far red is going to make your plants strech three meters, but they make the plant grow taller while blue makes for squat plants. If I added near uv I might add some far red to counter the anti strech. So far the 3500k leds seem to work just fine by themselves though.

 

[shaggyballs]

Yes, both red and far red can make plants elongate.
But
I am not sure blue light makes for squat plants.
Have you ever tried to veg under a 10K bulb?

As I stated it is the ratio of red to far red that is important.
I am not sure you are grasping the complete concept of it all.

But if your 3.5K leds are working good for you, that is all you may need to know.
My favorite color is 4K for flower.

Another tip.
Blue light will grow leafy plants no so much short plants.

What exactly are you referring to when you say anti-stretch?
I am not familiar with that term.

 

[indagroove]

My LED's have a pretty good amount of both blue and red in the spectrum to balance out the addition of far red:

@ 28 days flowering, stretch just ended:

 

[Horselover Fat]

Yes, both red and far red can make plants elongate.
But
I am not sure blue light makes for squat plants.
Have you ever tried to veg under a 10K bulb?

As I stated it is the ratio of red to far red that is important.
I am not sure you are grasping the complete concept of it all.

But if your 3.5K leds are working good for you, that is all you may need to know.
My favorite color is 4K for flower.

Another tip.
Blue light will grow leafy plants no so much short plants.

What exactly are you referring to when you say anti-stretch?
I am not familiar with that term.

Yes, blue will reduce cell expansion which in our case means shorter internodal lenght. Near uv will have the same effect, but more pronounced ie anti strech, which is obviously a real scientific term

I'm just telling you why I'm not adding them. I don't think it is worth the cost for me. I know white leds alone can grow 2+g/w. There's no point in investing in fine tuning untill I max out what these lights can do. Even then the FR photons would have to be much more effective than white led photons to offset the additional cost. This is only my second grow using these leds, but I've grown 300g in my 60x120cm using 315cmh and that was quite a bit of plant in there. I think my space is a more limiting factor than my light. Actually I don't think I'll ever reach even 2g/w if I run the light at full 320w. That would be 640g and that's just ridiculous I'd be very happy if I ever produced 400g in there. I know the light is able to deliver, but am I? If you find fr-leds add yield or quality for you - awesome!

 

[Mars Hydro Led]

Both red and far red elongate plants. I'm not saying a bit of far red is going to make your plants strech three meters, but they make the plant grow taller while blue makes for squat plants. If I added near uv I might add some far red to counter the anti strech. So far the 3500k leds seem to work just fine by themselves though.

 

[shaggyballs]

You seem to think I am encouraging you to add far red?
I am not, I was trying to be clear about the subject.

You never mentioned the importance of the ratio of far red to red.

My point was I think you are missing some subtle facts on the subject.
I asked you if you were aware of the effect of far red in a HPS.
You never responded to that.

You seem to be saying blue light will make plants squat.
Compared to what red light ?
How does it compare to white?
If blue light make plants squat as you state, should we be using a 10K bulb for veg if we want squat plants.


I am simply suggesting these is a bit more to this story than you are allowing for.
Not telling you that you need to use it.

 

[Horselover Fat]

You seem to be saying blue light will make plants squat.
Compared to what red light ?
How does it compare to white?
If blue light make plants squat as you state, should we be using a 10K bulb for veg if we want squat plants.

Yes.

Of course, yes.

I don't think green light has an effect on strech. I don't know of studies showing such effects.

I haven't used 10k mh bulbs. A lot of uv in the spectrum. Could work for veg, but there's probably better alternatives.

 

[saitama]

I did a run with 20% 730nm LED to 660nm LED with 4000k main lighting and my buds came out big, but very airy and not dense at all. I was very unhappy with the bud structure and I do believe it was due to the emerson effect. Perhaps I did not have the right ratio, but I no longer run the 730nm during day time, only 10 minutes after lights off. I also run a 13/11 schedule with the 730nm and a strain that supposedly takes forever to show sex (Malibu Pie), has shown sex today on day 4.

 

[Horselover Fat]

I did a run with 20% 730nm LED to 660nm LED with 4000k main lighting and my buds came out big, but very airy and not dense at all.

My buds got much more dense after switching away from hid. I know you can grow pretty dense buds under hid too, but for me the quality of the buds from my first led harvest was indeed much better. Small, hard and beautiful nugs.

 

[shaggyballs]

My buds got much more dense after switching away from hid. I know you can grow pretty dense buds under hid too, but for me the quality of the buds from my first led harvest was indeed much better. Small, hard and beautiful nugs.

What do you attribute the improvement to?

Color, coverage or intensity?

 

[saitama]

My buds got much more dense after switching away from hid. I know you can grow pretty dense buds under hid too, but for me the quality of the buds from my first led harvest was indeed much better. Small, hard and beautiful nugs.

This only happened when I ran the 730nm during the full cycle. Since I've switched to only 10m after dark, my colas got so dense that I had my first case of botrytis

 

[Horselover Fat]

What do you attribute the improvement to?

Color, coverage or intensity?

I'm guessing it's because of less far red and especially because of less infra red, which also increases cell expansion. The buds weren't fluffy like shaded lowers, but they weren't densely packed. I grow in small spaces so I used to run my cooltubed hps very close to canopy and having more distance to the plant would help in that regard, I think. I wish I grew more strains with the cmh. I only grew a single far too tightly packed grapefruit scrog and a couple of harvests of a low yield foxtailing sativa, so I don't really know how tight buds it would grow. I do know these are all great grow lights, but they are different from each other and make the plant behave a bit differently.

 

[shaggyballs]

So you think far red makes for fluffy buds.....hmmmm?

Not sure I agree with that statement, but thank you for the response!

Peace
Shag

 

[Horselover Fat]

So you think far red makes for fluffy buds.....hmmmm?

Not sure I agree with that statement, but thank you for the response!

Peace
Shag

I think I wrote

The buds weren't fluffy

It's just that the red end of the spectrum makes every stem grow a little longer. Inside the buds too.

Pictured is the last bud I have from my first led grow. It's just over a gram. The way I used hps my grams were always larger in volume. I'm not saying this is a perfect bud nor am I saying you can't grow this thight buds under hps. Just that the way I did it the buds were always larger, but not as dense. To me it seems that the spectrum difference is the most likely culprit. I can't prove it and I might be wrong. Only controlled studies with many plants can prove things. Everything else is speculation.

 

[Horselover Fat]

You might enjoy this overview of the current research on photobiology.

An Update on Plant Photobiology and Implications for Cannabis Production

This review presents recent developments in plant photobiology and lighting systems for horticultural crops, as well as potential applications for cannabis (Cannabis sativa and C. indica) plant production.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6455078/