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Let their be light! An open discussion about the science of light.


shaggy

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All topics welcome.

First topic of discussion.

 

Has anyone had success using more than 12 hours of light for flowering?
There is good research on this for Cannabis, showing the strong effect from increasing photoperiod by only 15 or 30 minutes from 12 hours (for drug biotypes).

 

 

The Effect of Electrical Lighting Power and Irradiance on Indoor-Grown Cannabis Potency and Yiel.pdf

Edited by shaggy
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@shaggy, seeing how having any control beyond what goes into the genetics, training if any, soil and water I'll just observe. Working on getting my basic math dialed before l take the graduate classes. I don't have to understand everything to find it interesting. I have had my mind stimulated by this sight constantly. Not just with bud porn either. But i like that too!

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On average Cannabis starts flowering outdoors at 14/10, indoors at 12/12. The reason for the difference is the presence of 730 nm light outdoors naturally. 730 nm light switches the plant from day to night,wake to sleep by flipping the phytochrome state. 730 nm lights have been available for indoor growing for years, I've been using it for around 6 years. Without 730 indoors it takes the plant 2 hours to transition the phytochrome state from day to night. 5 Minutes of 730 light after the main lights go out will flip the state so that you can run up to 14/10 indoors. I began using 730 to increase yield because of the extra energy the plant can take in with the longer schedule. Using 730 indoors as a trigger also seems to shorten flower by a week or more.

 

I also flower at around 600 PPFD scrog style.

 

 

 

PPFD efficiency.jpg

Edited by Captainmorgan
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I monkeyed with it @Captainmorgan for a run did a half assed set up seemed to work out I did notice a shorter flower cycle.. I'm gonna have to revisit this do a better set up..Thanks for reminding me my red LED's are just gathering dust..Make It Rain Reaction GIF

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2 minutes ago, Chronic2001 said:

@Captainmorgan are you running co2? What is your average yield per 4x4? Are you running a trellis or using stakes for support?  

For quality reasons I run the room around 82 so CO2 is not useful. I used to mostly do double screen horizontal scrog but designed a mobile vertical screen setup on wheels that is much easier and quicker to work on, I have a very bad back. I've yielded up to 2.2 zips per sq ft with less than 600 PPFD.

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I try to run for high quality and high efficiency. I build my own LED fixtures and I build them for high efficiency, more LEDs driven softer. The high efficiency along with the low PPFD make for a grow area without the need for AC. I find the combo of lower PPFD and temps makes for high terpene levels. I don't keep track of yields much these days, used to when I was experimenting with different lights and set ups. My current 4' tall by 6' wide vert screens can yield around 2 units with around 600 watts of LED when I veg them enough to fill the screen.

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1 hour ago, Captainmorgan said:

I also flower at around 600 PPFD scrog style

I like the quality of flower i get in the 600 par range "super frosty" but it's not as dense as the 800/1000 par area is.I personaly shoot for a average of 800. I feel that is my sweet spot for quality and yieid.All these assumption's are based on a Apogee 500 PAR meter.I also run LED/ HLG lighting.

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3 hours ago, Chronic2001 said:

@CaptainmorganDo you feel if you ran 1000 ppfd your quality would decline but your yield would increase? What is your average you normally hit per sq ft? 

Please don't let me step on toes here @Captainmorgan

 

@Chronic2001
This is no rabbit hole, it is a sink hole with no bottom.😋

I fell in round 2014 and have not hit the bottom as of yet.

There are a ton of factors to consider when trying to answer your question.

I feel for you, You don't know how many times I yelled at the screen saying.....

"Just answer the question, it ain't that hard, it is one question .....🤬WTF????🤬🤬

 

So anyways........

If you consider a scenario where the max photons hitting the leaf are exactly the same.

(That is to say, the Daily Light Integral is at full potential)

The plant can not use anymore photons at this point.

 

And the color AKA temperature are exactly the same.

The plants are clones fed exactly the same way.

The VPD is kept at a constant and exactly the same.

As I said sooo many things to factor into the equation in order to answer the question properly.

If you read even a little of the links I provided you were able to see all the shit that was given to a highly trained scientific team who have gone on to make big money in the cannabis industry.

 

Beta Test Team was on the cutting edge and provided a real scientific look at cannabis lighting. 

They were ridiculed for any misspoken word.

They were more or less run out of town.

I did my best to study under them for as long as they were around.

My point, as you are probably wondering bout now is..........🥴

I need to make sure I am not giving out flawed info.

At least to the best of my ability anyhow.😎

 

So back on topic here.....

 

You picture the scene everything is exactly the same on both sides photons are maxxed out.....

Now you have to consider something called midday depression.

Yes, that is when you leave the house without your weed and your morning buzz wears off.🤯

 

Well not really, but not a bad joke.

Now your thinkin' WTF is that right?
Google it for more on exactly what it is, I got a nice ramble on here already....LOL

 

It would seem that too many photons can actually slow photosynthesis.  

The decrease in photosynthetic rate appears to be due primarily to high leaf temperatures, there is also the decrease in stomatal conductance to consider here also. 

 

Ok now a real world report using a HLG 650R.

The top bud on my tallest plant was too close to the light, not enough to bleach or burn, not discolored a bit, green.

The top 3 inches of that bud are not really going to get smoked, it looks low quality at its finest.

If you have been around, you know by lookin at it, you don't need to smoke it, to be sure it is crap.

 

Clearly a case of too many photons slight excessive leaf temps too.

So what do we show from all this is you can not just increase your Photosynthetic Photon Flux Density and expect to increase yield and or quality.

 

Now I do not have one of them there fancy meters to tell you about the numbers but there is a ceiling.

Like in a house you just move up slowly until you hit the celling.

Like in a house when you hit the ceiling you know it.......lol

 

I hope I answered your question, I did the best I could without all the scientific jargon, links, quotes ect.

 

Good luck with your experiment, if you get some numbers share with the family.

 

Peace    :hookah:

Shag     

2 hours ago, oldschool said:

I like the quality of flower i get in the 600 par range "super frosty" but it's not as dense as the 800/1000 par area is.I personaly shoot for a average of 800. I feel that is my sweet spot for quality and yieid.All these assumption's are based on a Apogee 500 PAR meter.I also run LED/ HLG lighting.

Them there look like good number to me.....LOL

Nice job brother @oldschool

Edited by shaggy
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On my vert scrog screen the plant is only 1 foot deep at most hanging out both sides of the screen so 600 is plenty. Especially with my lights built for it, 9 quantum boards to cover 24 sqft, they have great penetration because the light comes from so many different angles so you don't need extra PPFD to penetrate through leaves. I sometimes run two verts back to back with 2 lights on the outside facing each other, so the light that passes through the plant shines on the backside of the other plant so the plant is surrounded by light. I get rock hard buds with this setup. When growing a natural plant without a screen I kick up the PPFD for more penetration.

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6 hours ago, shaggy said:

All topics welcome.

First topic of discussion.

 

Has anyone had success using more than 12 hours of light for flowering?
There is good research on this for Cannabis, showing the strong effect from increasing photoperiod by only 15 or 30 minutes from 12 hours (for drug biotypes).

 

 

The Effect of Electrical Lighting Power and Irradiance on Indoor-Grown Cannabis Potency and Yiel.pdf 110.44 kB · 2 downloads

@Chronic2001

Have you thought of increasing your photo period beyond 12 hours?

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@shaggy I have considered it after reading on the Emerson effect years ago but never tried it. 

 

If anything I'm always battling heat so ill dim or run shorter days. Quality is usually pretty good as long as the plants don't get to built up or my rooms don't get to hot.

 

In the last 100+ lights I've harvested I've averaged 2+ per 4x4. That's not great but considering some lights had plants hermie and get thrown out and 60+ or so of those lights were for pheno hunting so I had to sift through some plants that yielded almost nothing if it even made it into a tote to get trimmed instead of straight to the "to be processed" bin.

 

I did not keep track of what each light did by itself but im pretty sure I was close to 4 lbs for my best ever single 4x4 yield. Best average was 3lbs per 4x4 over a 10 light room.

 

Normally ill see around 2-2.25 range average per 4x4. Im trying to get closer to 3 per light while maintaining quality so I'm willing to try whatever will get me to that point. I just need to get my cooling under control then I can do some more controlled experiments.

 

I'm not new to reading about growing but I've only been actually growing for a little over 2 years now. Started in a 4x4 tent now I've got some room to play 😆.  I'm always trying to get better so keep the info coming.

 

 

It's hard for me to get into some threads and forums because all the bashing and misinformation you have to sort though so I pretty much quit looking at forums unless I have a specific question then ill Google it and do some reading through the mountains of crap. I gravitate more towards kis organic and grow from the heart type podcasts. I listen to Kevin Jodrey and shaping fire. Pretty much anything that has the "experts" talking about growing I'm listening. But I truly feel you can learn something from everyone! Even if its what NOT to do... 🤣

 

Happy growing everyone! 

 

I leave you with this.... around 3 weeks left on this pic. Not the best but not the worst either 💯 😉.

VideoCapture_20210311-072535.jpg

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@shaggy are we ever going to get together at an event or something? I would love to try some flower from you guys that been doing this a long time and concentrate on high quality over yield. I'm curious how my flower would stack up in the ring with yalls. Make it happen!  Damn cvoid....

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Not totally on topic, but I think you light gurus will appreciate it. 

   I think it's been at least 25 years, probably much longer.  If I'd been doing indoor all along I'd know. I just smoked tons of it!  My memory suffers now and then. My buddies lived in a small berg in Norcal. The were trying to get their indoor dialed. Pretty edgy guys from years of guerrilla stuff. Not a lot of information around or shared.  They figured out that the elect. meters rolled over! This tiny utility bought juice in bulk from the big guys and they lost track of it! Went on for years. These guys just blew up huge! They knew the bill was only going to be so much. Why grow only 20 when it cost the same to do 200. At least the utility part.  They got their gear figured out real good, for that time. The utility company figured out what was going in too. The whole zone was in on it. All new meters went in. The worst 10 guys paid $10K each to pay for all the meters.  They made so much money every one just coughed it up. Really got the indoor rolling in that area. 

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Ok, so I been browsing thru @Captainmorgan threads for quite a few years now atleast a few years before I came to this board, I finally just shifted to 13/11 using the 730's for 15 minutes at lights out, I lost my garden this last summer

because of serious real life shit but I'm slowly getting back on track. I need more time to make a good judgment but I have a close friends grow of this plant to compare to. Its a hulkberry in the middle of third week of flower. The breeder

says 9-10 which generally means 9 for me in hydro. she is def an amazon, tough to tell from the pic but I've prob bent 8 stems over already. I will def come back to thread when I have more info, but to my eye it is making a difference already.

DSC00232.JPG

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42 minutes ago, Chronic2001 said:

@Captainmorgan does the plant express itself differently?  What was the yield difference from when you used to run without the 730s?  I appreciate all the info. 

 

It made a noticeable gain for me, 13.5/10.5 gives you 12.5% more energy into the plant over 12/12. Now this may vary depending on your PPFD and if you're running a high PPFD and the plant is already getting it's DLI then you wouldn't run the longer schedule.

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I've always had better luck an yields health of plants running the gasoline routine 12 an 1 light were u run 12 hours on 5.5 hours off 1 hour on then 5.5 off You can even use a smaller light to run the 1 hour on as your just trying to break the hormones of the plant to stop budding!Once u drop the 1 hour on plants set flowers alot sooner in my book

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  • 8 months later...
On 3/10/2021 at 4:55 PM, crownpoodle said:

@shaggy, seeing how having any control beyond what goes into the genetics, training if any, soil and water I'll just observe. Working on getting my basic math dialed before l take the graduate classes. I don't have to understand everything to find it interesting. I have had my mind stimulated by this sight constantly. Not just with bud porn either. But i like that too!

I agree. Interest promotes research. I'm the type of person that dives deep into understanding my interest. But just because I have some knowledge doesn't mean I understand what I know. I'm interested in the effects different spectrums of light have on cannabis. Which spectrum promotes which hormone to be produced. How much is just enough and when pushing the limits how much is too much. There are so many areas of study in the subject of photosynthesis. Where to start is The question.

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  • 1 month later...

@Jace here is a good spot, I dropped some good knowledge here already.
My threads on icmag are real good too.
Check em out, ask me anything you wish, may not have the answer, but bet I can point ya in the right direction.

On 12/4/2021 at 5:44 AM, Jace said:

Where to start is The question.

 

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10 minutes ago, shaggy said:

@Jace here is a good spot, I dropped some good knowledge here already.
My threads on icmag are real good too.
Check em out, ask me anything you wish, may not have the answer, but bet I can point ya in the right direction.

 

@Jace careful... @shaggy will have waking up at 3am wondering about all sorts of random stuff. The answer is probably in the Z-library.

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18 minutes ago, crownpoodle said:

@Jace careful... @shaggy will have waking up at 3am wondering about all sorts of random stuff. The answer is probably in the Z-library.

Yep, misery loves company......🤫

Edited by shaggy
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