The far red thread

[GreenSanta]

If you have the patience to wait for your buds to ripen fully then you have time and patiences enough to learn what far red is all about. It is complicated and does different stuff at different times.

The Phytochrome System and Red Light Response.

Read this: https://www.boundless.com/biology/textbooks/boundless-biology-textbook/plant-form-and-physiology-30/plant-sensory-systems-and-responses-184/the-phytochrome-system-and-red-light-response-701-11926/

and this The Emerson Effect.

https://en.wikipedia.org/wiki/Emerson_effect

These are short not overly technical explanations on what far red can do.

Thanks for the links. I have buds ripening every week, I do not know patience lol.

Seriously I'll do more reading over the Winter but I'm buying lights now and wanted to see if I could score any easy info.

I don't think I'm gonna spend money on that yet.

 

[randydj]

Look at the ChilLeds they have red built into them and the spectrum is controllable!

 

[nfhiggs]

Ah, that's a good addition to the theorem.

It would work for plants too I guess. Lower down below the plants there is a higher fraction of FR light too

To an extent, yes, but we generally remove that lower growth anyway as it is never very productive.

 

[wietefras]

To an extent, yes, but we generally remove that lower growth anyway as it is never very productive.

True, but that is to be the whole point of stretch caused by FR light. To try and outgrow your neighbours

 

[Knowledgeiskey]

Building a far red supplemental coming along nice

 

[bonllu]

Hi, I´m just testing different light recipes to make a bulb lamp to control chrisanthemum flowering. My first try was only red 670 nm, but feedback from cultivars was not so good. They told me kinda of problems with morphogenesis in flowering. So I'm testing three light recipes now. I'm trying to simulate a wínter crop, so I turn the the main lights on (citizen PW horticulture spectrum) eleven hours and when main light is off it stars a cycle of 15min-on / 30 min-off for five hours to break the night and stick chrisanthemum to veg. Just as chrisanthemum growers told me they do. It works like 16/8 photoperiod which prevents flowering (chrisanthemum is short day plant, just like weed) Now I will change to 12/12 in order for them to flower and look at what happens.

The tent with the light recipe with FR content stretches much more than others. So, no discussion at all about if FR as EOD is good for streching. It is. You only need to add a few minuts FR EOD treatment and you will strech the knots. I set up the 12/12 this monday, I will observe them and I will notice if the recipe with FR content speeds the flowering up, that tent has to be the first one in displaying the flowering symptons.

I've posted three pictures. First one of the onset of the test, all the clones were the same height. Second picture 7 days later, you can see a few differences, and third picture 12 days later where differences in stretching are obvious.

 

[nachooo]

A quick question....I usually have about 10 watts of far red leds very well distributed over about 6,9 square foots or 0,64 square meters using them 10 minutes after main lights off. They do their job, and I think there is not too much streching,,,But to be sure....Is posible to run some UVA leds (365nm) (10-20 watts) at the same time that far red leds and avoid any strech at all...? Or will the UVA leds ruin the effect of the far red leds and eliminate the 2 hours advantage they provide?
Thanks for reading

 

[Photon Flinger]

Have the UVA go out 5 mins before the last reds. That will be enough to reset.

FYI, you might want to consider dialing back for the lights on period due to the extra light energy. My 80/90 CRI test are down to 6 hr lights on with a 1500-1850 PPFD @ 23c (real time temp!) and I plan on dropping that to 5.5 soon. In my opinion the more dark time you give them the less problems with flowering.

 

[nachooo]

Have the UVA go out 5 mins before the last reds. That will be enough to reset.

FYI, you might want to consider dialing back for the lights on period due to the extra light energy. My 80/90 CRI test are down to 6 hr lights on with a 1500-1850 PPFD @ 23c (real time temp!) and I plan on dropping that to 5.5 soon. In my opinion the more dark time you give them the less problems with flowering.

So you are using twice the usual PPFD in half the time...6/18? Are you using CO2? If not.... can the plants stand such light intensity without photoinhibition or bleaching problems? Or using 6 hours only allows them to grow without CO2?

 

[Photon Flinger]

No additional CO2, just good air circulation to keep temps in check.

That isn't intense at all. Plants can handle more, they just don't use it. The problems people run into are actually heat related and running the light too long causes what people think are mag issues.

This is where DLI comes into play - flower is fine between 14 and 45. Up to 65 is good for vegging.

 

[nachooo]

No additional CO2, just good air circulation to keep temps in check.

That isn't intense at all. Plants can handle more, they just don't use it. The problems people run into are actually heat related and running the light too long causes what people think are mag issues.

This is where DLI comes into play - flower is fine between 14 and 45. Up to 65 is good for vegging.

Thanks for the info...I am very interested..so if you dont mind other question...
Which one is the maximun ppfd you can use without CO2 in flowering at 10/12 with far reds at the end of day and at about 23 C day / 18 C night Pure sativa strain...?
I use dyna grow line for veg and flower..I have also dyna grow mag/pro to boost magnesium in flower (I usually dont need that) .that has mag covered in normal light situations... and also I have a pure mag solution from canna...How many mag should I add to avoid the mag problem you mention before? twice the usual amount? ppm?
Can this big ppfd amounts be used in veg time adding more mg and reducing light day time? For example: 14/10 instead of 18/6 or even using some kind of light gas routine like 12on/5off/2on/5off.
Thans again for your time and attention

 

[tomate]

Which one is the maximun ppfd you can use without CO2 in flowering at 10/12 with far reds at the end of day

I would say about 1000 ppfd so you get a solid DLI of 36 mol/d at 10/14.

Can this big ppfd amounts be used in veg time adding more mg and reducing light day time? For example: 14/10 instead of 18/6

You don't want the lights-off period to be longer than 6 hours and even this might be too long for some strains.

or even using some kind of light gas routine like 12on/5off/2on/5off.

This should work. Interrupting the dark period for a couple of minutes would be already sufficient. At the end it is up to you how fast you want them to grow depending on how much light you give them per day so every light shedule will do as long as you keep the lights-off period short enough.

 

[nachooo]

I would say about 1000 ppfd so you get a solid DLI of 36 mol/d at 10/14.


You don't want the lights-off period to be longer than 6 hours and even this might be too long for some strains.

This should work. Interrupting the dark period for a couple of minutes would be already sufficient. At the end it is up to you how fast you want them to grow depending on how much light you give them per day so every light shedule will do as long as you keep the lights-off period short enough.

Finally I have donde some quick calculations without taking in count the changes in led efficiency when you drive the higher..that means that at the end I should add some more watts but anyway:
I am using now 160 watts in veg 18/6 so I can use in veg to obtain same DLI also:
A gas lighting routine of 12/5/2/5 I will need about 205 watts
or
A gas lighting routine of 8/7/2/7 I will need about 290 watts
This is quite interesting...more in flower time of course
I wonder how the use of far red at the end of lights will interact with this gas lighting routines in veg will an 12/5/2/5 convert to a 12/7/2/7? Which will be the benefits? maybe the night time is better optimized to building process? Less stressed plants?

 

[Photon Flinger]

nachoo you are on the right track. Here are some other pieces of info you might find helpful.

1 DLI = 278 PPFD for 1 hour. For example, 10 hours @ 278 PPFD will give you 10 DLI whereas 10 hours of 550 PPFD will give you 20 DLI.

You can manipulate the DLI via time and light output. The magic number however is what the plant will take in, usually somewhere between 10-65 DLI. To make it even more complicated the light requirements are different for each stage of growth. Most people use a slow growth veg method whereas I am now leaning towards a higher DLI once the plants have reached a size that covers the light footprint. Prior to flip they will be at the same DLI going into flower and it seems to help with the transition.

I use GLR in veg since I have the light power and don't need to run 12 hrs per light cycle. To do 10/14 for example, 4 on, 5 off, 1 on, 5 off, 5 on, 4 off. You actually want to avoid FR in veg since it is the signal to sleep. Has little impact as DLI is king at this stage.

Most important in all of this is keeping temps down using good air circulation. I have run plants under 3500 PPFD with good temp control and didn't get any increase in yields over <1000 for the same 12/12 cycle. Lettuce can handle 5000 PPFD but it doesn't grow more. Good air circ also removes the need for CO2. In my opinion having to add additional CO2 just means that there isn't enough airflow so kill two birds with one stone. Hyper efficient LEDs let you keep ambient temps well within the 20-30c range which is optimal. Soon we will be spending more of our electricity on fans than lights.

And mag isn't a problem, more like dealing with symptoms and not a fix. The problem is the plant running out of mag to handle the excess light the cells are receiving. If you get your lighting dialed into the proper DLI that the plant wants then you won't have the issue.

 

[nachooo]

nachoo you are on the right track. Here are some other pieces of info you might find helpful.

1 DLI = 278 PPFD for 1 hour. For example, 10 hours @ 278 PPFD will give you 10 DLI whereas 10 hours of 550 PPFD will give you 20 DLI.

You can manipulate the DLI via time and light output. The magic number however is what the plant will take in, usually somewhere between 10-65 DLI. To make it even more complicated the light requirements are different for each stage of growth. Most people use a slow growth veg method whereas I am now leaning towards a higher DLI once the plants have reached a size that covers the light footprint. Prior to flip they will be at the same DLI going into flower and it seems to help with the transition.

I use GLR in veg since I have the light power and don't need to run 12 hrs per light cycle. To do 10/14 for example, 4 on, 5 off, 1 on, 5 off, 5 on, 4 off. You actually want to avoid FR in veg since it is the signal to sleep. Has little impact as DLI is king at this stage.

Most important in all of this is keeping temps down using good air circulation. I have run plants under 3500 PPFD with good temp control and didn't get any increase in yields over <1000 for the same 12/12 cycle. Lettuce can handle 5000 PPFD but it doesn't grow more. Good air circ also removes the need for CO2. In my opinion having to add additional CO2 just means that there isn't enough airflow so kill two birds with one stone. Hyper efficient LEDs let you keep ambient temps well within the 20-30c range which is optimal. Soon we will be spending more of our electricity on fans than lights.

And mag isn't a problem, more like dealing with symptoms and not a fix. The problem is the plant running out of mag to handle the excess light the cells are receiving. If you get your lighting dialed into the proper DLI that the plant wants then you won't have the issue.

I have been thinking...as the goal is reduce flowering times...maintaining same production and electricity cost..
If a 8/16 is done aumenting the PPFD adding about 33% more PPFD that in a 12/12 , then we got lesser flowering times due to very longer nights..with same DLI.
But adding far red treatment at the end of this 8 hours..is like 8/18...so more longer night....less flowering times again
At this point I would be using a DLI of about 38,5 about 1300 PPFD the 8 hours of light , before I was using same DLI with 1000 PPFD in 12 hours.
As Photon Flinger wrote the plant can take 10-65 DLI..DLI is refered to a 24 hours period if I understand well...
So we have a 8/16 timing that with far red is like 8/18...a day of 26 hours (indoor conditions)
Could be possible (maintaining the far red)... to use artificial days of less than 24 hours to reduce even more the flowering period? I mean like 8/10 day with far red will be like a 8/12..so flowering is possible... I understand that this is a lot of work with timers...sorry if you cant follow my logic cause english is not my native language
Could be this go further using a 6/10 with far red (6/12)? ..Instead of 24 hours day, 16 hours days... only 6 hours of light with high PPFD(about 1600), lot of ventilation and magnesium...Will it be possible? or I am thinking too much . A plant in a 16 hours day should accept 7-44 DLI?

 

[Photon Flinger]

I agree nachooo to a certain extent. There are other factors that need to be considered, the main one being the circadian rhythm which forces us to work with a 24 hour cycle no matter what.

FR is a signal that the sun is going away. When the sun sets, the last wavelengths are those from red on up so the plant takes that as a sign to start shutting down. If you wanted to, you could just use a flash of FR after all lights are out to get the same effect.

FR is also good for the plant in general as it doesn't have to condition photons for photosynthesis like it does blue. Emerson identified the PS1 and PS2 systems for photosynthesis using photons of 680nm and 700nm respectively. It is also easier on our eyes as a bonus.

It isn't so much as trying to reduce flowering times, but rather providing optimal flowering conditions that will maximize the plants' potential for the time it has to grow. Once achieved you want to reduce operational costs such as electrical and apply automation to reduce work.

Electrical savings can come from 1) better efficiency and 2) less running time. Both work together and act similar to the Emerson effect. As you use more efficient lighting, it gets more powerful for the same amount of electricity. That allows you to reduce the amount of time needed to provide light for plants to maximize their growth. Instead of running 12/12 for flower (or trying to run 14/10 with FR) I am going the other way running 6/18 which is another 50% reduction in electrical costs.

Each person will come up with what works best for them. I run 12 Vero 29c per 1m2 and can adjust them to run between 10w to 45w each. DLI is dialed in using 1500-1850 PPFD for flowering cycle; right now run time is 5.5/18.5 so about 30 DLI. 1500-1850 PPFD is roughly equivalent to a summer's day morning and late afternoon. The key to getting it at the canopy is keeping the lights close, the temps in check and making the most light with the least electricity. 12 Vero 29 SEs are roughly 400 bucks. Heat sink/frame, use a cookie sheet. Pay what you want for drivers, the cobs don't care so long as they are within the correct ranges.

 

[nachooo]

I agree nachooo to a certain extent. There are other factors that need to be considered, the main one being the circadian rhythm which forces us to work with a 24 hour cycle no matter what.

FR is a signal that the sun is going away. When the sun sets, the last wavelengths are those from red on up so the plant takes that as a sign to start shutting down. If you wanted to, you could just use a flash of FR after all lights are out to get the same effect.

FR is also good for the plant in general as it doesn't have to condition photons for photosynthesis like it does blue. Emerson identified the PS1 and PS2 systems for photosynthesis using photons of 680nm and 700nm respectively. It is also easier on our eyes as a bonus.

It isn't so much as trying to reduce flowering times, but rather providing optimal flowering conditions that will maximize the plants' potential for the time it has to grow. Once achieved you want to reduce operational costs such as electrical and apply automation to reduce work.

Electrical savings can come from 1) better efficiency and 2) less running time. Both work together and act similar to the Emerson effect. As you use more efficient lighting, it gets more powerful for the same amount of electricity. That allows you to reduce the amount of time needed to provide light for plants to maximize their growth. Instead of running 12/12 for flower (or trying to run 14/10 with FR) I am going the other way running 6/18 which is another 50% reduction in electrical costs.

Each person will come up with what works best for them. I run 12 Vero 29c per 1m2 and can adjust them to run between 10w to 45w each. DLI is dialed in using 1500-1850 PPFD for flowering cycle; right now run time is 5.5/18.5 so about 30 DLI. 1500-1850 PPFD is roughly equivalent to a summer's day morning and late afternoon. The key to getting it at the canopy is keeping the lights close, the temps in check and making the most light with the least electricity. 12 Vero 29 SEs are roughly 400 bucks. Heat sink/frame, use a cookie sheet. Pay what you want for drivers, the cobs don't care so long as they are within the correct ranges.

Thanks for the post..but you said you got a 50% reduction in electrical cost using 6/18 that is logical, but if you want to mantain production, you have to mantain DLI, so have to put more PPFD..in fact double it.. And even worst..if you run the leds twice the amps..you will have about10-15% less lumens per watt... At the end of the day you will spend some more watts...if you want to mantain same production and using the same leds...when you are reducing time at 6/18.. Am I right? this extra watts maybe are a few compared with the watts you save reducing flowering time...
Other question... if you use for example in flowering: 4on-2off-4on-14off.. will this timing have benefits over 8/16 assuming same DLI? Will the plants admit more PPFD with less heat and light stress due to the 2 hours rest ?
or will the plants become a little crazy and start to make bananas.....
Thanks for your reading

 

[Photon Flinger]

Thanks for the post..but you said you got a 50% reduction in electrical cost using 6/18 that is logical, but if you want to mantain production, you have to mantain DLI, so have to put more PPFD..in fact double it.. And even worst..if you run the leds twice the amps..you will have about10-15% less lumens per watt... At the end of the day you will spend some more watts...if you want to mantain same production and using the same leds...when you are reducing time at 6/18.. Am I right? this extra watts maybe are a few compared with the watts you save reducing flowering time...
Other question... if you use for example in flowering: 4on-2off-4on-14off.. will this timing have benefits over 8/16 assuming same DLI? Will the plants admit more PPFD with less heat and light stress due to the 2 hours rest ?
or will the plants become a little crazy and start to make bananas.....
Thanks for your reading

I am getting the high PPFD by using led hyper efficiently. 10w-45w adjustable means I can turn it up to provide more PPFD or cover a larger footprint. To get even coverage across the footprint they are running about 23w each for 280w, and with another 20w to air circulation, totaling 300w power cost per 1m2. Cranking them up to 45w each will put out 2800-3500 PPFD across the canopy which is just a waste of power.

You can increase PPFD by adding electricity or adding light sources.The more cobs you have drawing from the same power pool the more light you get. 2 cobs produce at least 120% light output using the same power as 1 cob yet 1/4 the heat. DLI goes up as more PPFD is produced so your electrical usage is the same.

I think that flower schedule may stress the plants. Can't answer the question. You could give it a try. I do know that using UV to stress for seeds works well.

 

[wietefras]

There are other factors that need to be considered, the main one being the circadian rhythm which forces us to work with a 24 hour cycle no matter what.

No, correlation does not imply causation. The fact that plants grown in a 24h rhythm correlate to a 24h rhythm doesn mean we are stuck with that rhythm.

I've seen people grow Cannabis on a 36 hour day or shorter days than 24h. All of those worked fine too. The rhythm simply adapts to the new day length.

I am getting the high PPFD by using led hyper efficiently.

That only costs more. There is an economical optimum and running the leds "hyper efficiently" is not economically optimal. Besides, you still have the DLI problem which nachoo referred too. So either way, you still end up paying more for the same DLI.

 

[nachooo]

I am getting the high PPFD by using led hyper efficiently. 10w-45w adjustable means I can turn it up to provide more PPFD or cover a larger footprint. To get even coverage across the footprint they are running about 23w each for 280w, and with another 20w to air circulation, totaling 300w power cost per 1m2. Cranking them up to 45w each will put out 2800-3500 PPFD across the canopy which is just a waste of power.

You can increase PPFD by adding electricity or adding light sources.The more cobs you have drawing from the same power pool the more light you get. 2 cobs produce at least 120% light output using the same power as 1 cob yet 1/4 the heat. DLI goes up as more PPFD is produced so your electrical usage is the same.

I think that flower schedule may stress the plants. Can't answer the question. You could give it a try. I do know that using UV to stress for seeds works well.

I understand, I dim the Veros 18 to 10 watts each one to get this high efficiency. Regarding UV stress, I knew a breeder that sprouted the seeds under lot of UVB light, he said that some seeds died, but the ones that survived will produce a more potent stuff... I dont know if is a good technique....