24/0 vs 20/4 light schedule?

[StimpLedNoTill]

Has anyone found a difference between 24/0 veg, 20/4 and 18/6? While vegging, cannabis doesn't require a dark period so is it just slower growth and better on the electric bill to give a dark period? Would also help with temps depending on grow environment. All input is always appreciated!

 

[Remystemple]

there's 2 camps on this one. the one that says the plants need a dark period and those who say they do fine without a dark period.

I've heard some say that 24/0 can cause hermies, but I use 24/0 for the first couple weeks of seedling with nothing bad happening yet.

I think the main thing i took away from my searching for this answer was that there's no difference and the 6 hours of dark saves energy costs was the main reason i use 18/6

 

[StimpLedNoTill]

there's 2 camps on this one. the one that says the plants need a dark period and those who say they do fine without a dark period.

I've heard some say that 24/0 can cause hermies, but I use 24/0 for the first couple weeks of seedling with nothing bad happening yet.

I think the main thing i took away from my searching for this answer was that there's no difference and the 6 hours of dark saves energy costs was the main reason i use 18/6

Hey, thank you for the reply, I had a feeling it really just came down to energy costs, I have heard that it could cause light stress which could be why ppl have said it causes hermies easier. I think it depends on how you subject them to the light though. I got my leds on a dimmer so I'm thinking giving them constant but less light then gradually increasing the intensity as they grow might help mitigate any stress caused by constant light. Just a thought though, always trying to gather info from everywhere possible!

 

[Remystemple]

Hey, thank you for the reply, I had a feeling it really just came down to energy costs, I have heard that it could cause light stress which could be why ppl have said it causes hermies easier. I think it depends on how you subject them to the light though. I got my leds on a dimmer so I'm thinking giving them constant but less light then gradually increasing the intensity as they grow might help mitigate any stress caused by constant light. Just a thought though, always trying to gather info from everywhere possible!

I feel like it might be good to have 24 if using c02. I might be wrong about that tho.

 

[StimpLedNoTill]

I feel like it might be good to have 24 if using c02. I might be wrong about that tho.

Well I think ambient co2 is around 400 which is more than enough for full growth and co2 is only needed past that as you add light intensity since they go hand in hand. So idk, it should be ok under 24hr light as long as you don't go over the level of light intensity that correlates to the amount of co2 that is taken in. Hopefully others chime in on this as well!

 

[Carcass]

I run my plants at 18/6 ,because it seems to me that my plants do a lot of their growing
during the dark period,kinda goes with the "they always look their best in the morning" thing.
My reason probably has no basis in fact ,but that's just how I do it.

Nature lets 'em rest a little,so I do too.

 

[Remystemple]

I run my plants at 18/6 ,because it seems to me that my plants do a lot of their growing
during the dark period,kinda goes with the "they always look their best in the morning" thing.
My reason probably has no basis in fact ,but that's just how I do it.

Nature lets 'em rest a little,so I do too.

This is one of the side by side experiments i'd like to try one day. after a few more grows. also after cloning goes a little smoother lol.

 

[Hdinkleman]

personally i treat my planta like my kids i want them to sleep. it might not make a difference, but i would always reccomend a dark period regardless of how long it is.

so my answer to this question would be stick with the 20/4 instead.

also, if you are going to run 24/0 light period make sure not to stress them with light

24 hr period is higher dli

 

[FelipeBlu]

It really depends on how much light you are able to provide. If you have some CFLs with a total PPFD of 150, then 24 hours (DLI of ~13) may be needed to get even adequate growth. If, on the other hand, you have a light pumping out a PPFD of 800, you could turn the light off after just 15 hours (DLI of ~43).

 

[StimpLedNoTill]

It really depends on how much light you are able to provide. If you have some CFLs with a total PPFD of 150, then 24 hours (DLI of ~13) may be needed to get even adequate growth. If, on the other hand, you have a light pumping out a PPFD of 800, you could turn the light off after just 15 hours (DLI of ~43).

This is what I wondered as well. So if you were to provide 800 ppfd, would going past the 15 hour mark just do nothing other than possibly stress the plant out?

 

[falstaffo]

i like sleeeeeep, i feel like most living things need sleep too Zzz

 

[FelipeBlu]

So if you were to provide 800 ppfd, would going past the 15 hour mark just do nothing other than possibly stress the plant out?

Not initially, and it depends on strain, but there is a point of diminishing returns (not necessarily 43 mol). And some strains have a lower tolerance for light, so you must always watch for light stress.

 

[SlyTown420]

Is 20/4 at 500-600 ppfd safe in veg?

 

[Hdinkleman]

It really depends on how much light you are able to provide. If you have some CFLs with a total PPFD of 150, then 24 hours (DLI of ~13) may be needed to get even adequate growth. If, on the other hand, you have a light pumping out a PPFD of 800, you could turn the light off after just 15 hours (DLI of ~43).

exactly, hit it on the head

sorry was assuming he was using a led light, but still i like my plants to have some dark time nonetheless

 

[Hdinkleman]

Is 20/4 at 500-600 ppfd safe in veg?

not about ppfd as much as it is total DLI
you can google and find a dli calculator online to make the conversion

 

[SlyTown420]

not about ppfd as much as it is total DLI
you can google and find a dli calculator online to make the conversion

Thanks @Hdinkleman

 

[FelipeBlu]

Is 20/4 at 500-600 ppfd safe in veg?

For almost all strains, this intensity and duration (also a DLI of 43) will result in excellent vegetative growth, if the distance from the light is not causing light stress. Some lensed LEDs are quite powerful, and the plant would be better off if the light was farther away, even if it meant a lower DLI.

Just to share the results of my experiments - a DLI of 15-20 is all that is required for excellent vegetative growth. Flowering though - give her at least 35, preferably 45-55.

 

[Hdinkleman]

this is not 100% accurate but can give you a rough idea.
its some calculator for wattage ppfd dli

https://dev.edman007.com/~edman007/pub/par-dli-cal.html

its a rough guide if you dont have a par meter and it tells you the dli down at the bottom of the report

for example my light running at 50% for 24 hours at 200 watts at 24” is a DLI of 75.

 

[fanleaf]

Has anyone found a difference between 24/0 veg, 20/4 and 18/6? While vegging, cannabis doesn't require a dark period so is it just slower growth and better on the electric bill to give a dark period? Would also help with temps depending on grow environment. All input is always appreciated!

Not so fast.
While it dont HAVE to have a dark period it is used by them for needed processes. I have grown in 24/0, 20/4, 18/6 and my plants have been bigger and healthier with 18/6 than any other schedule every single time. If you are using weaker lights then maybe your mileage may vary but yes, they do use the dark cycle.

 

[StimpLedNoTill]

Not so fast.
While it dont HAVE to have a dark period it is used by them for needed processes. I have grown in 24/0, 20/4, 18/6 and my plants have been bigger and healthier with 18/6 than any other schedule every single time. If you are using weaker lights then maybe your mileage may vary but yes, they do use the dark cycle.

Thank you for the reply, what processes are you referring to? My lights are weak atm, I have them dimmed to roughly 25% out of 630 total true led Watts, 315 Watts for each side of my 4x4 both on dimmers.