organic autos on gas lantern lighting

[calliandra]

Link the science? I didn't think the science of photosynthesis was up for dispute. If someone has proof that photosynthesis can continue in complete darkness, then ya I'd like to see that as well. But somehow I don't think that's going to happen.

The fact that photosynthesis can only happen in the presence of light is not in dispute.

http://hyperphysics.phy-astr.gsu.edu/hbase/biology/phoc.html

No it isn't.
I do admit that when I encountered the GLR, I was under the delusion that the "light-independent" part takes place at night. This seems to be a widespread misconception from the 80's - which is when I took my last biology classes lmao - but that's not disputing, that's just out of date haha

But it's not like plants just sit there and wait until the light comes back during the dark hours either.
In fact, in this time they convert the starches they made during the light times into sugars to feed themselves, breathe & continue their development.

Knowledge about these processes is commonly being gathered by studying Arabidopsis - for example, that the plant uses up 95% of the starch it stored the previous day irrespective of length of night - as long as the light-dark-rhythm remains within a 24hr cycle ("Circadian control of carbohydrate availability for growth in Arabidopsis plants at night". 2010, http://www.pnas.org/content/107/20/9458).
Yeah it's a different species, but (without knowing the details of how it was decided upon) I'm fairly confident they use this one because the results they get can be extrapolated onto other species too

So these guys found out that they could give the plant different light schedules and it would consistently use up 95% of its reserves.
Extrapolating this to our light schedules, it doesn't matter if the night is long or short, just that it has a night in which to use the goodies it produced. This actually would mean that the concept of plants having more time to "rest" with the GLR is indeed ineffective - whereby of course there could be details missing here
Sadly, I just saw that my own links don't really lead to any science either, just citations without source. I'm pretty sure I read about the benefits of the split night for general health in some non-weed-forum context too though, I may have to dig deeper and check through my bookmarks

But then the question arises, what if there is no night?
How can the plant compensate? Is the plant evolved to handle this situation elegantly or is it a tour de force?
I often am reminded of the fact that plants put up with a LOT of shit before they give up, so just because it works doesn't mean that's the healthiest way to go? (btw the same is true for my little GLR experiment haha)

So when you say, C3 plants can handle 24 hrs of light - yes I am aware there is experiential proof, but wheres the explanation?
Cheers!

 

[Resinhound]

Plants don't just sit and do nothing during the dark period, that's true. Because they can't do anything else during the dark period Except consume the fuel they managed to create during the day period. That doesn't mean plants Can't do these same processes concurrently. Obviously they do, Autoflowering plants are routinely grown on continuous light, plenty of proof of that. Unfortunately there isn't a ton of research on this as far as cannabis is concerned, we are kinda the cutting edge here. While in the case of fruiting plants there can be some argument for starch shuttling during dark periods, we aren't growing fruit.

Then there is the "health" argument... My autos all get 24 hour light from seed and are perfectly healthy. I don't see I'll effects from it, I only see increased growth rates over cycles with more dark periods.

I can see the argument for energy saving...a balancing act between yield and energy cost.

But by the same token I will say with longer light periods you can use less total wattage. I feel like you have to find a balance... Longer lights on times with lower intensity vs shorter light periods with higher light intensity. Personally I prefer lower intensity with 24 hour light, rather that blasting the hell out of my plants for 18 hours then letting them "recouperate" from the abuse. But that just my personal belief and observations. And only applies to automatics ofc.

 

[BobCajun]

I use a 6/2 cycle for veg mode myself, which I suspect would work well with autos too. It's something like the gaslight routine but more consistent and more total hours of light per day, 18. I find a short dark period really revitalizes them when the lights come back on. They get revitalized 3 times as often as 18/6 and none with 24/0. I find 1-3 hours dark is best. They don't need longer than that.

 

[calliandra]

Unfortunately there isn't a ton of research on this as far as cannabis is concerned, we are kinda the cutting edge here. While in the case of fruiting plants there can be some argument for starch shuttling during dark periods, we aren't growing fruit.

LOL you are, since your plants emanate ethylene (sorry I just couldn't resist haha )
The starches are transformed to sugars and used for plant growth btw.

But seriously, yeah it sure is a problem that there is so little cannabis-specific research, but IMO what we're talking here are general principles plants function by. And indeed, even taking the cannabis out of the equation, research is only just getting going in the quest of understanding the life of plants. There are just so many misconceptions out there that have become almost common knowledge but are part of an understanding that is mechanistic and chemical (which however is only part of the story) - and biased to serve the industries attached to that view.
Failing proper scientific research with adequate methodology, we still have experiential knowledge and logic as fallbacks. And while I am open to both, I do want to at least see it in action, as I have become extremely wary of the stuff we are teaching each other on these forums for said reasons.

So you say your plants grow on 24/0 and hey yes, they look great! But so do genetically modified veggies grown on chemical soup - and the nutritional content of those is more than doubtful. You can't see everything with your bare eyes. Of course we cannot expect us to do highly organized side-by-sides with painstaking analyses to determine whether indeed our plants are perfectly healthy using this or that method. But you never know, there are so many people exploring the possibilities that there could have been someone crazy enough to go through with something like that. Seems that's not the case for lighting/dark time... so I guess i have to go to bed hungry, my bad haha

I use a 6/2 cycle for veg mode myself

What's that? can you write out the cycle please?
Thanks


Meanwhile, I wasn't able to find the original reading I did on GLR and plant vitality However, I did find a line of research where experiments are being done with night interruption - mainly to prevent or induce flowering, BUT with noted side-effects of increased plant growth and vitality. Just two examples:

A study done on orchids:

"The effects of night interruption (NI) were examined on the vegetative growth and flowering of Cymbidium ‘Red Fire’ and ‘Yokihi’. Plants were grown under 9/15 h ambient light/dark (control), 9 h ambient light plus night interruption (22:00–02:00 h) with low light intensity at 3–7 μmol ^m−2 s−1 (LNI) and 9 h ambient light plus NI with high light intensity at 120 μmol ^m−2 s−1 (HNI) conditions. The number of leaves, leaf length, number of pseudobulbs and pseudobulb diameter increased in both LNI and HNI compared to controls for both cultivars."

(From the Abstract of "Night interruption promotes vegetative growth and flowering of Cymbidium", 2011, http://www.sciencedirect.com/science/article/pii/S0304423811004535)

A study on Dahlias:

"Experiments were conducted to evaluate effects of photoperiod on growth and dry-weight partitioning in Dahlia sp. ‘Sunny Rose’ during both seedling (plug) production and subsequent production in 10-cm pots. Plugs were grown under short days [9-hour natural photosynthetic photon flux (PPF)] or long days (same 9-hour PPF plus a 4-hour
night interruption with incandescent light). Total plant dry weight was unaffected by photoperiod; however, long days (LD) inhibited tuberous root development and increased shoot dry weight, fibrous root dry weight, leaf area, shoot length, and number of leaf pairs.
Long days reduced plug production time by ≈1 week compared with short days (SD).
Following transplanting to 10-cm pots, shoot growth and foliar development were superior under LD. There was no effect of photoperiod on foliar N concentration. The superior growth of LD plugs following transplanting can be attributed to the plant being in a physiological state conducive to shoot expansion instead of storage."

(from the abstract of "Night Interruption Lighting Is Beneficial in the Production of Plugs of Dahlia ‘Sunny Rose’", 2000, http://hortsci.ashspublications.org/content/35/7/1244.full.pdf)

So, based on these kinds of observations, it's easy to see how the GLR could get connected to increased plant health and vitality. However, I couldn't find any studies that explicitly examine this either. lol

Cheers!

 

[BobCajun]

Regarding the 6/2 light cycle I mentioned, I just found a page that recommends it. I used the cycle on my own without seeing it anywhere else but it appears that somebody else happened upon the same idea and found it beneficial. Weird how I had that idea and Resinhound didn't.

"While there are many approaches to veg light cycles for cannabis, a 6/2 schedule allows for maximum plant growth. A 6/2 schedule allows plants to process more intense light, prevents plants from becoming stressed and puts less stress on your cooling system. It’s a win all around. Give your plants a break every 2 hours and you’ll be amazed at the results."

 

[Resinhound]

LOL you are, since your plants emanate ethylene (sorry I just couldn't resist haha )
The starches are transformed to sugars and used for plant growth btw.

But seriously, yeah it sure is a problem that there is so little cannabis-specific research, but IMO what we're talking here are general principles plants function by. And indeed, even taking the cannabis out of the equation, research is only just getting going in the quest of understanding the life of plants. There are just so many misconceptions out there that have become almost common knowledge but are part of an understanding that is mechanistic and chemical (which however is only part of the story) - and biased to serve the industries attached to that view.
Failing proper scientific research with adequate methodology, we still have experiential knowledge and logic as fallbacks. And while I am open to both, I do want to at least see it in action, as I have become extremely wary of the stuff we are teaching each other on these forums for said reasons.

So you say your plants grow on 24/0 and hey yes, they look great! But so do genetically modified veggies grown on chemical soup - and the nutritional content of those is more than doubtful. You can't see everything with your bare eyes. Of course we cannot expect us to do highly organized side-by-sides with painstaking analyses to determine whether indeed our plants are perfectly healthy using this or that method. But you never know, there are so many people exploring the possibilities that there could have been someone crazy enough to go through with something like that. Seems that's not the case for lighting/dark time... so I guess i have to go to bed hungry, my bad haha


What's that? can you write out the cycle please?
Thanks


Meanwhile, I wasn't able to find the original reading I did on GLR and plant vitality However, I did find a line of research where experiments are being done with night interruption - mainly to prevent or induce flowering, BUT with noted side-effects of increased plant growth and vitality. Just two examples:






So, based on these kinds of observations, it's easy to see how the GLR could get connected to increased plant health and vitality. However, I couldn't find any studies that explicitly examine this either. lol

Cheers!

Point taken, however I'd just like to point out the fact that orchids and dahlias are both CAM plants not C3 plants so that easily explains the increased growth due to dark periods.

 

[Resinhound]

Regarding the 6/2 light cycle I mentioned, I just found a page that recommends it. I used the cycle on my own without seeing it anywhere else but it appears that somebody else happened upon the same idea and found it beneficial. Weird how I had that idea and Resinhound didn't.

"While there are many approaches to veg light cycles for cannabis, a 6/2 schedule allows for maximum plant growth. A 6/2 schedule allows plants to process more intense light, prevents plants from becoming stressed and puts less stress on your cooling system. It’s a win all around. Give your plants a break every 2 hours and you’ll be amazed at the results."

Why everyone feels the need to blast their plants with as much light as possible is beyond me.... If you use less intensity and longer light periods, your plants don't get stressed. This is all I'm saying... You don't have to run them to exhaustion every 6 hours... You can jog them lightly for 24 instead and photosynthesis never stops.

I think someone needs to make a fixture with a programmable dimming function or better yet randomize it. To simulate periodic cloud cover.Couple this with a light mover to simulate the sun moving across the sky... Then we are getting somewhere

 

[RM3]

Why everyone feels the need to blast their plants with as much light as possible is beyond me....

because they don't understand how to properly tweak the environment, light bein just one of many factors.

 

[Resinhound]

Regarding the 6/2 light cycle I mentioned, I just found a page that recommends it. I used the cycle on my own without seeing it anywhere else but it appears that somebody else happened upon the same idea and found it beneficial. Weird how I had that idea and Resinhound didn't.

"While there are many approaches to veg light cycles for cannabis, a 6/2 schedule allows for maximum plant growth. A 6/2 schedule allows plants to process more intense light, prevents plants from becoming stressed and puts less stress on your cooling system. It’s a win all around. Give your plants a break every 2 hours and you’ll be amazed at the results."

A 6/2 light schedule COULD increase growth.


It's an opinion, unfortunately no more valid than mine.

 

[Fevs]

Interesting discussion here. I live in England, so in the winter it gets cold, I use 24-0 then with great results. Well expensive on electricity, but it also heats my home. In the summer it's too hot to run 24-0, I go for 4 or 5 hours dark period at the hottest part of the day. I notice more stretch when I have a dark period. Sometimes the plants can grow a bit compact under 24-0, but can just back the light off. For me, 24-0 is worth it with auto's just to keep constant perfect temps and avoid the plants getting too cold. Auto's do without doubt love constant light. If it wasn't too hot, I'd run 24-0 24/7 - 365

 

[Resinhound]

Exactly what I've been saying forever, darkness promotes stretch. If you want compact plants.... Dont make them hunt for the light they are always looking for . I use dark periods as a tool, when I want to promote stem growth, I add them. But that's not often, mostly after. A FIM, a topping or when I want to hurry lst along.

 

[Fevs]

20-4 growth. 1st pic is 20-4, other pic 24-0. They seem to love the dark period, but the others love 24-0. Either way, hard to say. A lot can depend on the lights, no point growing tall plants with a 250w hps. No point growing compact plants with a 600w hps either. Maybe it's just a matter of personal preference. I tent to ignore the science and just grow what the plants I'm growing like. Compact plants are younger, but you get the idea of what 4 hours darkness does to my plants.

 

[calliandra]

20-4 growth. 1st pic is 20-4, other pic 24-0. They seem to love the dark period, but the others love 24-0. Either way, hard to say. A lot can depend on the lights, no point growing tall plants with a 250w hps. No point growing compact plants with a 600w hps either. Maybe it's just a matter of personal preference. I tent to ignore the science and just grow what the plants I'm growing like. Compact plants are younger, but you get the idea of what 4 hours darkness does to my plants.View attachment 3760540

View attachment 3760539

same strain?

 

[Fevs]

No, but they are all Sweet seeds auto's which are very similar to each other in the way they grow. The taller one's looked compact last week. They looked almost identical, so expect the compact plants to grow loads this next 7 days. Even then the 24-0 plants are having a dark period too from now. They had a good start on 24-0. The taller plants are not the same strain either, 4 Sweet afghan's and 4 fast bud#2.

 

[BobCajun]

That's the problem with several hours of darkness in a cycle, stretching. But what about say 7/1 repeating? How much stretching could 1 hour of dark at a time cause? Here's an experiment to try, one plant on 21/3 and another on 7/1.

 

[Fevs]

It's really not a problem for me with 4 or 5 hours darkness. I get a bigger yield when they stretch 'a bit', as more light gets to the whole plant. The secondary branches in an auto grow are so important. Getting them to stretch up, then hitting them with the lights sweet spot once they stop stretching, is exactly what I aim for. Some people are adamant 20-4 is better than 24-0, again personal preference to suit a growing style. I like both 24-0 and 20-4. I wouldn't do a dark period for more than 6 hours, really don't think auto's need to be asleep for that long.

I'd like to see a grow on 7/1, but I'm not doing that myself, I'd like to watch another grower do that

 

[BobCajun]

It's really not a problem for me with 4 or 5 hours darkness. I get a bigger yield when they stretch 'a bit', as more light gets to the whole plant. The secondary branches in an auto grow are so important. Getting them to stretch up, then hitting them with the lights sweet spot once they stop stretching, is exactly what I aim for. Some people are adamant 20-4 is better than 24-0, again personal preference to suit a growing style. I like both 24-0 and 20-4. I wouldn't do a dark period for more than 6 hours, really don't think auto's need to be asleep for that long.

I'd like to see a grow on 7/1, but I'm not doing that myself, I'd like to watch another grower do that

Pretty much need LED for the multiple on/off per day cycles. HIDs will degrade faster the more they're started. I use CFLs in veg so not a big problem, though I'm sure it will shorten their life somewhat.

 

[calliandra]

Exactly what I've been saying forever, darkness promotes stretch. If you want compact plants.... Dont make them hunt for the light they are always looking for . I use dark periods as a tool, when I want to promote stem growth, I add them. But that's not often, mostly after. A FIM, a topping or when I want to hurry lst along.

To me, what you are observing there could be precisely the plant taking the opportunity to do that starch conversion thing undisturbed to promote her growth So maybe our ideas of the plant "hunting for light" is misleading as the mechanism that actually drives this may be quite another in some cases (but not in others - a stretchy plant under wonky lighting is definitely hunting for light! )

Why everyone feels the need to blast their plants with as much light as possible is beyond me.... If you use less intensity and longer light periods, your plants don't get stressed. This is all I'm saying... You don't have to run them to exhaustion every 6 hours... You can jog them lightly for 24 instead and photosynthesis never stops.

Regarding the 6/2 light cycle I mentioned, I just found a page that recommends it.

Interestingly, this article (thanks for that one, BobCajun, it's a real lead!) links to a highTimes piece that in turn leads to a paper from Purdue University (Commercial Greenhouse Production. Measuring Daily Light Integral in a Greenhouse, https://www.extension.purdue.edu/extmedia/HO/HO-238-W.pdf) about the concept of "Daily Light Integral". This is a unit calculated from the total photon count that hits a m² per day and is used in greenhouse management.

The underlying principle:

"Each crop species has an optimal light intensity that maximizes photosynthesis and plant growth. When there is not enough light, growth and crop quality can decline; and if there is excessive light, photosynthesis and growth will not increase despite the expense of keeping the lights on."

There is no differentiation as to lengths of light/dark periods, just how many moles of photons in 24 hours. So yeah, there should be no problem whether that optimal DLI is reached by shorter times of intense light or longer times of weaker light.

So according to this principle, Resin can run his 24hr low light setup, Bob can run his 6/2 thing at higher wattage, and I would need the highest wattage with the 13 hrs of the GLR to reach that X of photons in the time available (I am reminded of the 450W lights the guy in the GLR autos vid was using )

Question is, what is the optimal DLI for cannabis?

This article seems to address this question somewhat:
Light dependence of photosynthesis and water vapor exchange characteristics in different high Δ9-THC yielding varieties of Cannabis sativa L., 2015.
http://www.sciencedirect.com/science/article/pii/S2214786115000078

Highlights
• Light dependence of photosynthesis was studied in Cannabis sativa varieties.

• Considerable variation in light response of photosynthesis was observed.

• Cannabis showed greater adaptability potential at higher light levels.

• Higher biomass and yield in C. sativa can be achieved if grown under high PPFDs.

 

[Resinhound]

To me, what you are observing there could be precisely the plant taking the opportunity to do that starch conversion thing undisturbed to promote her growth

I guess my question would be why then does that growth mostly consist of fibrous stem material.

Logic would dictate the plant is stretching for a reason.

 

[BobCajun]

To me, what you are observing there could be precisely the plant taking the opportunity to do that starch conversion thing undisturbed to promote her growth So maybe our ideas of the plant "hunting for light" is misleading as the mechanism that actually drives this may be quite another in some cases (but not in others - a stretchy plant under wonky lighting is definitely hunting for light! )



Interestingly, this article (thanks for that one, BobCajun, it's a real lead!) links to a highTimes piece that in turn leads to a paper from Purdue University (Commercial Greenhouse Production. Measuring Daily Light Integral in a Greenhouse, https://www.extension.purdue.edu/extmedia/HO/HO-238-W.pdf) about the concept of "Daily Light Integral". This is a unit calculated from the total photon count that hits a m² per day and is used in greenhouse management.

The underlying principle:


There is no differentiation as to lengths of light/dark periods, just how many moles of photons in 24 hours. So yeah, there should be no problem whether that optimal DLI is reached by shorter times of intense light or longer times of weaker light.

So according to this principle, Resin can run his 24hr low light setup, Bob can run his 6/2 thing at higher wattage, and I would need the highest wattage with the 13 hrs of the GLR to reach that X of photons in the time available (I am reminded of the 450W lights the guy in the GLR autos vid was using )

Question is, what is the optimal DLI for cannabis?

This article seems to address this question somewhat:
Light dependence of photosynthesis and water vapor exchange characteristics in different high Δ9-THC yielding varieties of Cannabis sativa L., 2015.
http://www.sciencedirect.com/science/article/pii/S2214786115000078

So you need 1600-2000 micromoles per m2. According to this list, that would be one 1000w HPS or two 600w or three 400w. A very convenient coincidence.

400w
1. Philips Agro 400w 230v 660 uMol (output stabile, extra blue spectrum)
2. Philips Greenpower 400w 230v 725 uMol (output stabile)

600w
1. Philips SON-T plus 600w 230v 1045 uMol (output "instabile") output degrades fast
2. Philips SON-T Greenpower 600w 230v 1100 uMol (output stabile)
3. Philips SON-T Greenpower 600w 400v 1150 uMol (output stabile)
4. Philips SON-T Greenpower 600w 400v EL* 1170 uMol (output stabile) *specialy for high frequency electronic ballast >100.000 hertz

1000w
1. Philips SON-T Greenpower 1000w 400v EL* DE 1925 uMol (output stabile) in reality the lamp gives 2100 uMol at the start of its lifetime.
source