lighting Indoor chilli light cycles

Hi guys I'm just wondering what people's thoughts are on light cycle times for chillis. I've had mine on 18hrs on 6hrs off and have just changed to 12/12 to see what happens. They're already flowering.

What's ya thoughts?

Sent from my EVA-L09 using Tapatalk

I've got mine on 16/8 for no other reason than too lazy to plug in timer. They go off at 10pm when I go to bed and on at 6am when I wake up.
 
What is the reason for 12/12. Are you trying to force more flowering ?

KAOS said:

I've got mine on 16/8 for no other reason than too lazy to plug in timer. They go off at 10pm when I go to bed and on at 6am when I wake up.
 
What is the reason for 12/12. Are you trying to force more flowering ?

Click to expand...

No real reason, just wondering what might happen. Shouldn't do any damage? Lol

Sent from my EVA-L09 using Tapatalk

I swear by the vegetative light cycle 18hrs on and 6 off .... switching to the flowering phase light cycle I am a 12 on 12 off ... I read in a hydroponic magazine that by switching to the flowering light cycle (12/12) tricks the plant into thinking that it is later in the season which makes the plant work harder to try and catch up by producing more flowers ... if it works for you that's all that matters

Photo periods dont matter with peppers. This year I ran 4-6hr cycles and pepper plants flowered no different than running an18/6.
 

Trident chilli said:

I swear by the vegetative light cycle 18hrs on and 6 off .... switching to the flowering phase light cycle I am a 12 on 12 off ... I read in a hydroponic magazine that by switching to the flowering light cycle (12/12) tricks the plant into thinking that it is later in the season which makes the plant work harder to try and catch up by producing more flowers ... if it works for you that's all that matters

Click to expand...

 
That only matters with cannabis plants as they are photoperiod dependent
Pepper plants flower based on their age relative to the size of the container
 
Anything from 10-18 hours of light is fine. 

I didn't think it made a difference with peppers. Will probable change it back to 18/6 as the on time suits me better

Sent from my EVA-L09 using Tapatalk

I run a 16/8 cycle...Unless your growing weed, then I'd go from a 18/6 to 12/12 or even a 10/14..The drastic reduction in light will cause your buds to pop..With hot peppers you'll just stress the plants..
 

There's some support for using 24/0 light/dark until fruting and then lowering to 20/4 light/dark. As previous posters have said, Capsicum spp. is not photoperiodic so presumably the more light the better (up until limits in e.g. carbon metabolism).

Save money and do 12/12. No reason to run 18/6 for peppers. They will grow, flower, and produce all year in their natural habitat around the equator with somewhere between 10 and 14 hours of light per day.

austin87 said:

Save money and do 12/12. No reason to run 18/6 for peppers. They will grow, flower, and produce all year in their natural habitat around the equator with somewhere between 10 and 14 hours of light per day.

Click to expand...

 
Yes, of course they will grow, flower and produce. None of us is doubting that. However, just because the sun is on the other side of the earth about half a day each day naturally doesn't mean this is the ideal optimum if you want the best yields.
 
The article I linked, which is open access by the way (yay!), states this in their abstract:

Increasing the photoperiod to 16 or 20 hours increased pepper plant yields, but continuous light (24 hours) decreased yields compared to the 20-hour photoperiod.
 
Thereby my statement of there being some support for such light cycles. If you want some more arguments, just read some in the conclusion. Here they state e.g.:
 
Our results show that supplemental lightning increased yields of sweet pepper plants, especially during spring (March and April), and that the best photoperiod is 20 h. The increased yields were mainly due to an increase in the number of fruit harvested, but also to some increase in the average fruit mass.
 
They also to propose an elegant explanation to why 24 hours wouldn't be even better:
 
Extending the photoperiod to 24 h increased leaf starch accumulation (and soluble sugars contents at certain periods of the day). The fact that the pattern of...
...
Therefore, if starch and sugar accumulation is involved in the development of the negative effects, such as decreased growth and yields and leaf deformations, caused by continuous light on pepper plants, it is most likely that this accumulation is the result of a limitation within the leaf, probably the carbon metabolism.
 
Increased starch and sugar content is what you expect to gain from more light since this is the plants way to store the energy it gets from the light. This extra stored energy it can then utilize to good stuff, like growing more and producing more fruits and giving you larger fruits. You'd likely be thrilled by this.
 
Why they didn't see even better results with 24 h they then explain by the carbon metabolism getting choked up by continuous light. There's a bottleneck somewhere in the leaf which we are hitting when not giving the plant some rest. Therefore 20 hours, not 24 hours, if you want maximum yields.
 
"Save your money" you say. Sure you can I say. They will survive. You're right. However, since it costs me less than a dollar a day to keep my lights on and less than 30 cents to go from 12 to 20 hours of light that's what I'm doing. That's like 3 coffees a month for me. I'm happy to give that treat to my peppers. But to each their own!

I agree with the 20 on 4 off method. There needs to be a rest cycle for the plants. But in all fairness, i have grown plants under 24/7 light and they've done fine. I will say though, that all my peppers i'm growing this year were under 24/7 lighting during hardening off to the outdoors over a course of 2 weeks and their growth was stunted for about 2 weeks after that. Not sure if its related but just an observation.

SwedishGhost said:

 
Yes, of course they will grow, flower and produce. None of us is doubting that. However, just because the sun is on the other side of the earth about half a day each day naturally doesn't mean this is the ideal optimum if you want the best yields.
 
The article I linked, which is open access by the way (yay!), states this in their abstract:


Increasing the photoperiod to 16 or 20 hours increased pepper plant yields, but continuous light (24 hours) decreased yields compared to the 20-hour photoperiod.
 
Thereby my statement of there being some support for such light cycles. If you want some more arguments, just read some in the conclusion. Here they state e.g.:
 
Our results show that supplemental lightning increased yields of sweet pepper plants, especially during spring (March and April), and that the best photoperiod is 20 h. The increased yields were mainly due to an increase in the number of fruit harvested, but also to some increase in the average fruit mass.
 
They also to propose an elegant explanation to why 24 hours wouldn't be even better:
 
Extending the photoperiod to 24 h increased leaf starch accumulation (and soluble sugars contents at certain periods of the day). The fact that the pattern of...
...
Therefore, if starch and sugar accumulation is involved in the development of the negative effects, such as decreased growth and yields and leaf deformations, caused by continuous light on pepper plants, it is most likely that this accumulation is the result of a limitation within the leaf, probably the carbon metabolism.
 
Increased starch and sugar content is what you expect to gain from more light since this is the plants way to store the energy it gets from the light. This extra stored energy it can then utilize to good stuff, like growing more and producing more fruits and giving you larger fruits. You'd likely be thrilled by this.
 
Why they didn't see even better results with 24 h they then explain by the carbon metabolism getting choked up by continuous light. There's a bottleneck somewhere in the leaf which we are hitting when not giving the plant some rest. Therefore 20 hours, not 24 hours, if you want maximum yields.
 
"Save your money" you say. Sure you can I say. They will survive. You're right. However, since it costs me less than a dollar a day to keep my lights on and less than 30 cents to go from 12 to 20 hours of light that's what I'm doing. That's like 3 coffees a month for me. I'm happy to give that treat to my peppers. But to each their own!

Click to expand...

It is really all relative. Someone who's running several 1000w MH or HPS has a significantly higher cost than your $1/day. And I'd venture that someone running a setup like that would see minimally increasing yields at significantly much higher cost, relatively speaking, in going from 12 to 20 hours per day.

I'm also skeptical that a linear increase in light equates to a linear increase in yield. For instance, going from 12 to 20 hours is 66% increase in light hours, and thus cost. Does it produce a 66% increase in yield?! There are definitely situations where increasing light per hour (adding lights) can increase yield more effectively than more hours of lesser light.

So while you are right, the advice of "20 hours per day of light is best for everyone and their chili plants" isn't right. Each situation is different. As you said, to each their own.

Also, I wasn't able to find the link to the article you mentioned. If you don't mind, please do re-share. I would like to check it out. I'm curious as to their methodology and setup. And I might learn something

Added: I found the article in your previous post. Good read. But yield is not linear on addition of light, not even close. The study is also done in a greenhouse with supplemental light, not pure indoors.

I would venture that any lights that supplement the sun in a greenhouse can only do so much. The sun is mighty powerful.

Would be interesting to see an experiment done indoors that examines both extended photoperiods (12, 16, 20, 24) and traditional 12/12 photoperiods with more and/or higher intensity lights, also taking into account the cost of each method.

SwedishGhost said:

There's some support for using 24/0 light/dark until fruting and then lowering to 20/4 light/dark. As previous posters have said, Capsicum spp. is not photoperiodic so presumably the more light the better (up until limits in e.g. carbon metabolism).

Click to expand...

 No science involved ,
but due to extreme laziness I have run  24/7 lights for up to 6 weeks without any problems.

Good discussion people! Thanks!
 

austin87 said:

It is really all relative. Someone who's running several 1000w MH or HPS has a significantly higher cost than your $1/day. And I'd venture that someone running a setup like that would see minimally increasing yields at significantly much higher cost, relatively speaking, in going from 12 to 20 hours per day.

I'm also skeptical that a linear increase in light equates to a linear increase in yield. For instance, going from 12 to 20 hours is 66% increase in light hours, and thus cost. Does it produce a 66% increase in yield?! There are definitely situations where increasing light per hour (adding lights) can increase yield more effectively than more hours of lesser light.

So while you are right, the advice of "20 hours per day of light is best for everyone and their chili plants" isn't right. Each situation is different. As you said, to each their own.

Also, I wasn't able to find the link to the article you mentioned. If you don't mind, please do re-share. I would like to check it out. I'm curious as to their methodology and setup. And I might learn something
 

Click to expand...

 
Indeed. You're of course totally correct. My response was initially a bit fueled by what I interpreted as a bit dismissive on your side ("no reason" etc.), I must admit, and I'm sorry for that.
 
You will hit diminishing returns and the increase in electricity could end up not being affordable for you or economically unsound if you're a professional, depending on your setup. In my case I am willing to pay a bit more for faster growth and larger yields, but this is because pepper growing is a hobby for me and I would like to see them thrive as fast and fully as possible. There's a reason I've bought my soil components, prepared them carefully and not just picked it for free from outside. There's a reason I bought horticultural oil and did not end up using straight vegetable oil. And so it goes. It's more than cost saving and frugal priorities for me and more about caring the best* for my pepper plants. Again, to each their own.
 
* Well up to a point of course. I'm not rich!
 

austin87 said:

Added: I found the article in your previous post. Good read. But yield is not linear on addition of light, not even close. The study is also done in a greenhouse with supplemental light, not pure indoors.

I would venture that any lights that supplement the sun in a greenhouse can only do so much. The sun is mighty powerful.

Would be interesting to see an experiment done indoors that examines both extended photoperiods (12, 16, 20, 24) and traditional 12/12 photoperiods with more and/or higher intensity lights, also taking into account the cost of each method.

Click to expand...

 
Indeed it's not linear. I would however like to add that even for a professional, non-linear increased yields might be worth it. Why? Because electricity costs might not be the only, or even a, cost-limiting step (depending on setup). It might be space or overhead, where acquiring more square feet or plants might be way more costly. Of course, more light (e.g. the increase in starch and soluble sugars during the day) could also lead to other benefits (e.g. better pest resistance or root system), which are not immediately obvious from a single trial.
 
Regarding your comment on artificial lights versus the sun, I must strongly disagree there. It's all just numbers. On the equator you got 1 kW pure light per square meter. Let's be generous and say, maybe 30% is usable by the plant (e.g. see chlorophyll absorption spectra). Pepper plants can't handle full equator sun but needs some shade, so let's take it down to by a third. 200 W per square meter (about the efficiency of a modern solar panel, btw)? Easily done with LEDs since they are nearly 100 % efficient and the wavelengths of the light can be tailored to be fully ideal.
 
I'm not saying most setups are like this, where they can match the sun in terms of light, but I'm saying that this is achievable with some care and planning. That it would be impossible is a myth. It's a bit non-trivial when you discuss what light spectra is truly the best etc. (e.g. LEDs might not be the best if you're not spot-on here and without LEDs you loose a lot of efficiency) but light is not magic. It's just electromagnetic radiation at certain frequencies at certain intensities. We can reproduce it.
 
Indeed it would be interesting! There might be something of that kind out there so it could be worth looking for.

Good discussion indeed! Thank you, too!
 

SwedishGhost said:

Good discussion people! Thanks!
 
 
Indeed. You're of course totally correct. My response was initially a bit fueled by what I interpreted as a bit dismissive on your side ("no reason" etc.), I must admit, and I'm sorry for that.
 
You will hit diminishing returns and the increase in electricity could end up not being affordable for you or economically unsound if you're a professional, depending on your setup. In my case I am willing to pay a bit more for faster growth and larger yields, but this is because pepper growing is a hobby for me and I would like to see them thrive as fast and fully as possible. There's a reason I've bought my soil components, prepared them carefully and not just picked it for free from outside. There's a reason I bought horticultural oil and did not end up using straight vegetable oil. And so it goes. It's more than cost saving and frugal priorities for me and more about caring the best* for my pepper plants. Again, to each their own.
 
* Well up to a point of course. I'm not rich!
 
 
Indeed it's not linear. I would however like to add that even for a professional, non-linear increased yields might be worth it. Why? Because electricity costs might not be the only, or even a, cost-limiting step (depending on setup). It might be space or overhead, where acquiring more square feet or plants might be way more costly. Of course, more light (e.g. the increase in starch and soluble sugars during the day) could also lead to other benefits (e.g. better pest resistance or root system), which are not immediately obvious from a single trial.
 
Regarding your comment on artificial lights versus the sun, I must strongly disagree there. It's all just numbers. On the equator you got 1 kW pure light per square meter. Let's be generous and say, maybe 30% is usable by the plant (e.g. see chlorophyll absorption spectra). Pepper plants can't handle full equator sun but needs some shade, so let's take it down to by a third. 200 W per square meter (about the efficiency of a modern solar panel, btw)? Easily done with LEDs since they are nearly 100 % efficient and the wavelengths of the light can be tailored to be fully ideal.
 
I'm not saying most setups are like this, where they can match the sun in terms of light, but I'm saying that this is achievable with some care and planning. That it would be impossible is a myth. It's a bit non-trivial when you discuss what light spectra is truly the best etc. (e.g. LEDs might not be the best if you're not spot-on here and without LEDs you loose a lot of efficiency) but light is not magic. It's just electromagnetic radiation at certain frequencies at certain intensities. We can reproduce it.
 
Indeed it would be interesting! There might be something of that kind out there so it could be worth looking for.

Click to expand...

 

I did 16/8 and then moved to 18/6. All was indoor,i would say they did about the same. I would not do less than 16 and i would not do more than 18 but thats just me. Temps were the biggest factor in growth not the light,a slight warmer room makes a huuuuge difference in growth over 24hr. So look at proper ventilation and some heat in your grow box.

Sent from my GT-I9190 using Tapatalk

Gonzo said:

I did 16/8 and then moved to 18/6. All was indoor,i would say they did about the same. I would not do less than 16 and i would not do more than 18 but thats just me. Temps were the biggest factor in growth not the light,a slight warmer room makes a huuuuge difference in growth over 24hr. So look at proper ventilation and some heat in your grow box.

Sent from my GT-I9190 using Tapatalk

Click to expand...

 
Seems like a good move. Temperatures sure do make a difference, especially it seems wise to avoid stepping outside a 10-30°C/50-86°F interval, but I've not yet decided on a good temperature to aim for. My grow cupboard at the moment has no supplemental heating but exceptionally good ventilation which means that photoperiod and nyctoperiod temperatures are approximately the same (22°C/71°F vs. 19°C/66°F or so). What do you use?