Red & far red lighting

[direless]

So I am currently running 6 240w qb boards and 4 blurbles from mars hydro (the 96 reflector series) in a 6x6 which give me a ppfd of approx. 1000 or better when all lights are on. I start and end my "day" with the blurbles for half hour at each end. I then run 4 qbs and the blurbles for 4 hours at ppfd of approx. 700. I then run all lights for four hours in the middle of the "day".

I am looking at running red and far red either in addition to the blurbles or in place of the blurbles. My first question is should I run the blurbles or just add the reds. My second question is about when to run the reds. My understanding is there is a back and forth movement between Pr and Pfr if you run both red lights together this will enhance budding. Then start my day with red and finish with far red approximately 15-20 at each end with red helping to stimulate pf response to activate photosynthesis and far red to stimulate Pfr to more rapidly shut down up .

I do have a Co2 burner for the high ppfd and generally my room runs at around 650 to 700 ppm of Co2 without the burner. so I am thinking that I only need to run that for the 4 hours that I have all lights on.

Any help clarifying this would be greatly appreciated.

 

[Emilya Green]

The traditional use of far red in greenhouses is by using them as trigger lights. Twenty minutes at the transition from day to night and night to day hastens the plant's ability to transition from mode to mode. Scientifically, we think that plants use this far red (which naturally happens as the sun is within 5° of the horizon) to determine where they are in relation to the horizon, and this allows them to better judge their needed height in order to reach the light. Using far red trigger lights helps keep internodal lengths short and helps to produce more compact plants. Today there are studies to find out if this light is beneficial full time, or like UV, maybe best used only during portions of the day.

 

[Old Salt]

GrowMau5 has many good videos on YouTube for lighting. Apogee has videos for cannabis lighting as well, narrated by a university professor, drawing on material he teaches.

 

[direless]

wow quick responses.

Thanks Emilya, I think I get the "trigger" response but am looking at the process moving Pf and Pfr back and forth that can enhance bud development. I also am wondering about the need for Co2 at levels below 1000 ppfd and whether it is better to just run my burner which causes heat and environmental issues or is I can just run it during high ppfd.

Thanks Old Salt, I will look into growmau5 a little further I have seen some on led builds.

 

[WillCall]

Phytochrome Regulation of Flowering in the Long-Day Plant, Hyoscyamus niger - PMC

A daylength extension with incandescent light is more effective in promoting flowering of long-day plants like Hyoscyamus niger than fluorescent light. A low phytochrome photoequilibrium (Pfr/Ptot), attained by a far-red irradiation at the close of ...

www.ncbi.nlm.nih.gov

Plant Physiol. 1982 Sep; 70(3): 898–900.

Phytochrome Regulation of Flowering in the Long-Day Plant, Hyoscyamus niger1
Robert J. Downs and Judith F. Thomas

"A low phytochrome photoequilibrium (Pfr/Ptot), attained by a far-red irradiation at the close of long days under fluorescent light, also promotes flowering."


Has anyone gotten good results. This should make it possible to give the plants a long day (and all that extra energy) through the flowering cycle.

 

[Icemud]

Here is a writeup I did on one of my old grow journals that explains the 2 main uses of Far red. Hopefully it is helpful:


1. Flower trigger manipulation (used during the flowering cycle, after the regular grow lights go off for the day, the FAR RED light comes on as these lights go off, and stays on for anywhere from 15 mins to 2 hours afterwords(during the start of the dark period).

Red light converts the chemical phytochrome Pr (red) into phytochrome Pfr (far red). In the short day plants red light, 660nm begins the synthesis of PR and red light converts this to Pfr. Now this conversion of Pr to Pfr in light is a very fast process but at night, the process reverses and is slow, changing the PFR back to PR... Unless there is more PR than PFR, the plant will remain in veg..

HOW the flowering trigger with FAR RED Light works, is instead of the nightly process of PFr converting back to PR which is slow, adding FAR RED light after the sunlight/daylight goes out, will quickly convert the PFr to PR, instead of it taking all night, it takes just a few minutes of Far RED light to do this... Therefore because plants flower due to long interrupted nights, this process usually requires roughly 12 hours of uninterrupted dark, but when you use FAR RED, then you actually can get away with a shorter night, and longer day pushing the daylight of flowering up to 14 or 15 hours of daylight and only 9-10 hours of night, because the long night isn't needed with the FAR red converting the PFR to PR.

This is also the same reason that the GAS LANTERN ROUTINE works for veg, but in opposite....
By interrupting the dark cycle with 1 hr of light (RED or including red) , the PR is converted back quickly to PFR, so the plant stays in veg, because there again is more of an abundance of PFR than PR...typically this process as we know it for short day plants takes around 12+ hours of darkness to achieve a full reversion. So by breaking the cycle up, the plant will not flower.

2. Emerson Effect:

The emerson effect is a different thing from IR being used as a flowering trigger. *used during the daylight period...

The Emerson effect relates to photosynthesis. To be sort of general about it, there are 2 reaction centers involved with photosynthesis. Photosystem II (P680) and Photosystem I P700.

Photosystem I or P700 takes in electrons from IR light or light >680nm

Photosystem 2 or P680 takes in electrons from <680nm.

Emerson was experimenting with red and far red light and determined that when using both red and IR light together, photosynthesis was greater than using either IR or RED by themselves. This helped to the realization that there were 2 photosystems but also shows adding "some" IR light to the daylight is beneficial as well.

This ratio of red to far red can effect the morphology of the plant (how it grows) and with a low ratio of RED to FAR red this typically will cause plants to stretch more, as well as effect the traits of the leaf size. With a Higher Red/Far Red ratio, this typically will create less stretchy plants... So the goal with FAR red is to have some, but not too much, even though the sun is nearly a 1.2 :1 ratio.

 

[WillCall]

This is perfect! Thanks! I grow outside and not looking for large plants. Been planting at the solstice to keep the size modest and that is working for me. But if I planted earlier June and could trigger the plants early July then they could finish in the warmer/drier part of the late summer instead of Fall. I've found some FarRed LEDs at LedSupplydotcom and calculated the power they emit and it should only take a few to flood a small garden. Will have to try this next year.

Again, many thanks!

 

[safeman]

The traditional use of far red in greenhouses is by using them as trigger lights. Twenty minutes at the transition from day to night and night to day hastens the plant's ability to transition from mode to mode. Scientifically, we think that plants use this far red (which naturally happens as the sun is within 5° of the horizon) to determine where they are in relation to the horizon, and this allows them to better judge their needed height in order to reach the light. Using far red trigger lights helps keep internodal lengths short and helps to produce more compact plants. Today there are studies to find out if this light is beneficial full time, or like UV, maybe best used only during portions of the day.

Budget Led's is the answer UV use the last 3-4 weeks before harvest You are talking about Deep pentration with the red's

 

[WillCall]

Kalaitzoglou P, van Ieperen W, Harbinson J, van der Meer M, Martinakos S, Weerheim K, Nicole CCS and Marcelis LFM (2019)
Effects of Continuous or End-of-Day Far-Red Light on Tomato Plant
Growth, Morphology, Light Absorption, and Fruit Production.
Front. Plant Sci. 10:322.
doi: 10.3389/fpls.2019.00322

It is a misconception that there is more far-red at the end of the day. Read the paper above. They report a PSS ratio of ~0.70 for full daylight; this is the basis of the natural night measuring that controls flowering. You are confusing the shaded stretching response to the floral triggering role of phytochrome. While plants stretch as part of the flowering response too, they can stretch from shading in a non-floral response. We are discussing flowering control.

 

[safeman]

great information - learned a lot have 2 - 240 boards and one of them is the Flower board by them (budget led) series2 other full spectrum veg/flower /uv series 3 I believe

 

[Icemud]

Kalaitzoglou P, van Ieperen W, Harbinson J, van der Meer M, Martinakos S, Weerheim K, Nicole CCS and Marcelis LFM (2019)
Effects of Continuous or End-of-Day Far-Red Light on Tomato Plant
Growth, Morphology, Light Absorption, and Fruit Production.
Front. Plant Sci. 10:322.
doi: 10.3389/fpls.2019.00322

It is a misconception that there is more far-red at the end of the day. Read the paper above. They report a PSS ratio of ~0.70 for full daylight; this is the basis of the natural night measuring that controls flowering. You are confusing the shaded stretching response to the floral triggering role of phytochrome. While plants stretch as part of the flowering response too, they can stretch from shading in a non-floral response. We are discussing flowering control.

Yep.. its called shade avoidance syndrome. Basically under a "canopy" of plants, the most abundant light is green, and far red.. therefore the ratio of far red to red is much higher, so this increased ratio causes the plants morphology to grow to push the plant up out of the shade and into the sun. With adding far red, this can simulate the same "under canopy" ratios and cause the plant to stretch. Light induced plant growth is called photomorphogenesis.

 

[safeman]

Yep.. its called shade avoidance syndrome. Basically under a "canopy" of plants, the most abundant light is green, and far red.. therefore the ratio of far red to red is much higher, so this increased ratio causes the plants morphology to grow to push the plant up out of the shade and into the sun. With adding far red, this can simulate the same "under canopy" ratios and cause the plant to stretch. Light induced plant growth is called photomorphogenesis.

more great info - three things need for growing Genetics/Light/medium

 

[WillCall]

Four things needed. Genetics/Light/Medium/Friends!

 

[safeman]

Four things needed. Genetics/Light/Medium/Friends!

WOW !!!!!!!!!!!!!!!!!!!!!!!!

 

[WillCall]

WOW !!!!!!!!!!!!!!!!!!!!!!!!

I'm in the hills of western Mass. Legal here. That was last year's garden. But those plants are WAY more than I need. I had planted June 7 last year. I planted on the Solstice this year to keep the plants smaller. Even so they are pretty large (recent picture attached) with White Widow at 4.5 feet now and just starting budlets. That's why I want to try to trigger flowering with Far-Red treatment after dark, starting maybe July 15. Naturally they start flowering Aug 1 to Aug 20 (for different varieties) and finish Oct 1 to Oct 15; if I could get them moving into flowering July 15 with Far Red, they I would only need the lights about 2 wks and then natural short days prevail and I could pack up the Far-Red lights and maybe the plants would finish some weeks earlier when it is not so cold, damp - and no hurricanes to rip them apart. Anyway that is my idea and I think I'll set up this winter and experiment with the amount of Far-Red intensity needed to trigger flowering see if it would be practical to flood the garden with some suspended FR LEDs; one of those papers I cited used 17 μmol m−2 s−1 of 730nm LED for their Far-Red treatment; I assume they used that after some tests to know it was a solid effect. Hurricane on our doorsteps now. I have all my cages tied into a mesh network to keep from toppling the cages/plants. Hope things survive. Isaias tipped things and broke some branches last year. Henri is supposed to be much worse.

 

[safeman]

I'm in the hills of western Mass. Legal here. That was last year's garden. But those plants are WAY more than I need. I had planted June 7 last year. I planted on the Solstice this year to keep the plants smaller. Even so they are pretty large (recent picture attached) with White Widow at 4.5 feet now and just starting budlets. That's why I want to try to trigger flowering with Far-Red treatment after dark, starting maybe July 15. Naturally they start flowering Aug 1 to Aug 20 (for different varieties) and finish Oct 1 to Oct 15; if I could get them moving into flowering July 15 with Far Red, they I would only need the lights about 2 wks and then natural short days prevail and I could pack up the Far-Red lights and maybe the plants would finish some weeks earlier when it is not so cold, damp - and no hurricanes to rip them apart. Anyway that is my idea and I think I'll set up this winter and experiment with the amount of Far-Red intensity needed to trigger flowering see if it would be practical to flood the garden with some suspended FR LEDs; one of those papers I cited used 17 μmol m−2 s−1 of 730nm LED for their Far-Red treatment; I assume they used that after some tests to know it was a solid effect. Hurricane on our doorsteps now. I have all my cages tied into a mesh network to keep from toppling the cages/plants. Hope things survive. Isaias tipped things and broke some branches last year. Henri is supposed to be much worse.

quite a bit of work - moving - BUT sure is worth it ; the more effort/care really increased yields. Looking at least 1lb per plant ? have to remember your "cycles" for the reds