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

Does cannabis need far red light?

Is timing of exposure important?

What are the benefits?

Speculation is welcome.
Let's hash this out.

I think far red maybe for the signaling of flower to induce summer stretching of the plants. I switched my hps to a hps conversion mh ushio this run after the 3rd wk and my plants look better than usual this run. Personally, i have no scientific learning than what i pull from these boards for cannabis.

shaggyballs said:

Does cannabis need far red light?

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Yes. All plants do (that I know of).

This is a very basic concept. There is no debate about this issue.

Here's a video you may like, this is sound info. This should give you a good base of understanding from where you are right now:

How Does Red And Far-Red Light Impact Crops?
http://www.greenhousegrower.com/video/plant-culture/v-how-does-red-and-far-red-light-impact-crops/

shaggyballs said:

Is timing of exposure important?

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No. Not to simply grow plants if there's enough far-red (725 to 735 nm; peak is 730 nm) from the light source, and esp. relative to red (655 to 665 nm; peak is 660 nm).

However, as I and other have pointed out before, there are other uses for red and far-red light in terms of photoperiodism and flowering response. Research "night break" and "end-of-day" far-red light treatments, as well as the other topics I suggested you research in your other thread (see below).

Cannabis flowers due to changes in the night length (mainly), it senses the changing dark hours per day (diurnal period) using far-red light and red light. As well as Cannabis can flower due to age for some genotypes in unfavorable lighting conditions (like if the night isn't long enough).

Far-red light is used for these things by growing plants, including Cannabis:
photosynthesis
photoperiodism
flowering induction (for some species, such as Cannabis sativa L.)
photomorphgensis
phototropism
(etc.)

shaggyballs said:

What are the benefits?

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Here's what I already wrote to you in your other thread on this topic:

"No. Far-red isn't something you would want to add to your spectrum normally, unless for very special use-cases (not photosynthesis)."

"FAR-RED:

In terms of not adding extra far-red I was referring to white light. If you have a LED array, you need to add far-red if it's not already provided by the LEDs.

Read up on "phytochrome photoequilibrium," "phytochrome," "photoperiodism," "red far-red ratio," "shade avoidance reaction," and "Emerson effect" to get a better understanding about use of far-red light by plants.

We want a red:far-red ratio of around 1 to less than 4 for indoor lighting. Sunlight is 1.05 to about 1.2 in the day, and about 0.6 to 0.8 at sunrise and sunset.

For PPE (aka PPS, "phytochrome photoequilibrium") we want about 0.8 to 0.9, sunlight is about 0.5 to 0.72, except at sunrise and sunset when it's much lower."

shaggyballs said:

Speculation is welcome.
Let's hash this out.

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Speculation is not needed; there's no debate on this issue.

You should Google around for knna's past writings on this topic of using far-red and red light to affect plant photoperiodism (for example, shorter nights to flower) and photomorphgensis; he has the best writing on this for Cannabis of anyone we've ever read.

lostenspace said:

I think far red maybe for the signaling of flower to induce summer stretching of the plants. I switched my hps to a hps conversion mh ushio this run after the 3rd wk and my plants look better than usual this run. Personally, i have no scientific learning than what i pull from these boards for cannabis.

Click to expand...

You are pretty much correct in terms of plant reaction to far-red light (relative to the amount of red light), but it's not a summer light response (the same thing happens in spring and fall, too).

What you're referring to termed "shade avoidance reaction." It just means when there's too much far-red light (725 to 735 nm; peak is 730 nm) relative to red light (655 to 665 nm; peak is 660 nm) the plant thinks it's shaded, so it grows more (stretches) to try to get above the shade.

Shaggy, here a few research papers and studies you may want to review if you want more info about these topics. "End-of-day treatment" is also a common use for far-red LEDs:

Applications of Far‐Red LEDs in Plant Production under Controlled Environments
http://leds.hrt.msu.edu/assets/Uploads/Univ.-of-Arizona-Greensys-FR-EOD-presentation-2011.pdf

Photosynthetic activity of far-red light in green plants
http://ac.els-cdn.com/S000527280500...t=1411842847_aeaa5ebee6c8e544ae152e0841aeaed1

The long-wavelength limit of plant photosynthesis
http://ac.els-cdn.com/S001457930500...t=1411842881_7d44d2abca5769601e59fc6f58798240

Horticultural lighting − present and future challenges
https://www.icmag.com/ic/showpost.php?p=6572290&postcount=101

Photosynthetic Efficiency and Phytochrome Photoequilbria Determination Using Spectral Data
https://mega.co.nz/#!m40HFQbB!wtujIooa14CZOUy7RS2inQBX2lQU2-qgoSmsyr9dwXM
http://leds.hrt.msu.edu/assets/Uploads/Univ.-of-Arizona-Greensys-FR-EOD-presentation-2011.pdf

WOW....Thanks a sh*t load!!!
I am sorry, some of your wonderful references I have yet to read.

You're welcome.

If you check out any of those links, the video and the first link about LEDs will probably be best for you. Once you have a better understanding of the base issues the other documents may interest you, too.

shaggyballs said:

Is timing of exposure important?

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Many scientists say the FR is mostly needed right after the lights go out.

shaggyballs said:

What are the benefits?

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The plants get a lot more sleep and develop significantly better.

Bubbleblower said:

Many scientists say the FR is mostly needed right after the lights go out.


The plants get a lot more sleep and develop significantly better.

​

You wish​

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I have heard it both ways ....a good and a bad effect.
I assume it must be finely tuned.
Just the right amount emitted and the amount of absorption for the correct duration at the exact time needed.

No small feat from where I stand?????
But
I ordered a Kind LED with far red, gonna try it out.
Not really sure how to maximize the far red feature on it.
Any advice is welcome, scientific is best!
Thanks
shag

Short and sweet.
http://growlightsource.com/products/the-flower-initiator-and-booster-grow-lights/

If you need a parts list to build your own, let me know.

Beta Test Team dropped some good info here.
Thanks again Beta!
We miss ya!

FR activates ps1 over ps2 photosynthetic pathways...

Plants need both but ps1 isnt activated by red or blue.. because of this emerson effect far red is useful throughout a plants life.. the sun supplies plenty of fr and the benefits are quickly noticeable assuming your lighting is lacking at all in far red.

Its perceived by plants as shading when it hits them so they tend to stretch more due to its influence. Green is also.. both are really important for plant health.

Lost in a SOG said:

FR activates ps1 over ps2 photosynthetic pathways...

Plants need both but ps1 isnt activated by red or blue.. because of this emerson effect far red is useful throughout a plants life.. the sun supplies plenty of fr and the benefits are quickly noticeable assuming your lighting is lacking at all in far red.

Its perceived by plants as shading when it hits them so they tend to stretch more due to its influence. Green is also.. both are really important for plant health.

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That is exactly right, and the right answer for the question about far-red.

You can read some of the studies made by Emerson and his colleagues after his death. SUPER interesting, that people went into very crazy experiments, they did not know all things we now consider very basic knowledge.

Thank God that people existed and exists!

Are you adding supplemental far red light to your grow?

shaggyballs said:

Are you adding supplemental far red light to your grow?

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No. I don't want my plants to stretch any more than they do now. I don't think it would add anything else, but who knows.

Horselover Fat said:

No. I don't want my plants to stretch any more than they do now. I don't think it would add anything else, but who knows.

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Give this thread a good read and you may have a different opinion after a knowledge infusion.:friends:

shaggyballs said:

Give this thread a good read and you may have a different opinion after a knowledge infusion.:friends:

Click to expand...

I've read it. Good info in there. End of day treatment might be an interesting experiment, but I think it would only be useful in experimenting with a shorter night cycle.

There's a bit of far red too in white led spectrum and plants seem ok with the light. Would I yield more with added far-red? Well... more photons is more photons of course, but I'm not even close to maxing out the current ones yet. FR would strech the plants more and that would not be good.

These are just my opinions though. I don't think there's actual research into this. Bruce Bugbee found no difference in yield regardless of the spectrum they used in flower, but iirc FR wasn't tested.

Are you aware of the far red effect from HPS?

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).

just started flipping on the "bloom" switch on my LEDs that i use in veg, i had been only running the veg switch for quite some time