Duration of light on indoor plants

[Wargul]

I have a couple of photo-period seedlings under lights. At the moment I'm running the lights 24 hours because this spring has been a bit cold. Is this a problem or do they need a few hours of darkness?

 

[Sedge]

No they will be fine on 24/24,,,They’ll get plenty of sleep when they go to 12/12.

 

[Wargul]

No they will be fine on 24/24,,,They’ll get plenty of sleep when they go to 12/12.

Cheers Sedge.

 

[Indy]

While we're on the subject..

It sort of crossed my mind a couple of times over the last few years. But i have wondered if there's any pro's or con's to a Three Phase Lighting Schedule? Like First phase, 24hrs for the first 3-6 weeks. Second, 18hrs for the next 3-6 weeks. Then wrap up the final flower phase for 12hrs for the remainder of the grow?

 

[puggle6]

While we're on the subject..

It sort of crossed my mind a couple of times over the last few years. But i have wondered if there's any pro's or con's to a Three Phase Lighting Schedule? Like First phase, 24hrs for the first 3-6 weeks. Second, 18hrs for the next 3-6 weeks. Then wrap up the final flower phase for 12hrs for the remainder of the grow?

Look up Emerson effect, while not exactly what you are describing it is similar in way of mimicking sunrise and sunset color spectrums to stimulate more photosynthesis

For OP, while unlikely to be an issue, there is a possibility going from 24/0 to 12/12 immediately at flip could be a stressor

 

[thefullspectrum]

From my undestanding, It all depends on how much light youre pumping into them.

The (no added co2) guides suggest 600-900ppfd for veg, around 40 DLI. Thats usually acheived in 18 hours or maybe never with shit lighting??

It has its knockers but the Photone app on modern I-phone gives you a pretty rough guide, good enough for most of us. A little extra light, going above 40 DLI wont hurt them but is probably just a waste a power. Speaking of which...

Just got my latest power bill... Fuck me.
Never running the heater again. Its ran from an inkbird, only used it for half the Winter billing period, but easily doubled the usual grow cost. I had my suspicions this was coming, hence turning it off mid grow resulting in stunted plants from the cold. The sacrifices we make hey!

 

[R3za92]

While we're on the subject..

It sort of crossed my mind a couple of times over the last few years. But i have wondered if there's any pro's or con's to a Three Phase Lighting Schedule? Like First phase, 24hrs for the first 3-6 weeks. Second, 18hrs for the next 3-6 weeks. Then wrap up the final flower phase for 12hrs for the remainder of the grow?

Plants don’t care so much about the light other than decreasing light levels below a set length (12/12ish). They more care about dli, once you hit dli plants benifit from a rest period.

 

[R3za92]

Just got my latest power bill... Fuck me.
Never running the heater again. Its ran from an inkbird, only used it for half the Winter billing period, but easily doubled the usual grow cost. I had my suspicions this was coming, hence turning it off mid grow resulting in stunted plants from the cold. The sacrifices we make hey!

I tell people to switch their led out for a hps in winter instead of running a heater for exactly that reason.

Leds are great where temps are good or when it’s hot as leds means less cooling (so less ac) needed

 

[Indy]

Plants don’t care so much about the light other than decreasing light levels below a set length (12/12ish). They more care about dli, once you hit dli plants benifit from a rest period.

Yeah, it's was idea I wasn't too sure about for quite some time. Until I heard of DLI a few months back.

I have been working with DLI formula the last couple of weeks with the LED light. But it appears I managed to burn the plants doing so even though if had it around 32. I'll have to get a better light meter than my phone. Because having it at 32 was meant to be on the mild side. At my stage of the plants they called for 42.

 

[Porky]

From my undestanding, It all depends on how much light youre pumping into them.

The (no added co2) guides suggest 600-900ppfd for veg, around 40 DLI. Thats usually acheived in 18 hours or maybe never with shit lighting??

It has its knockers but the Photone app on modern I-phone gives you a pretty rough guide, good enough for most of us. A little extra light, going above 40 DLI wont hurt them but is probably just a waste a power. Speaking of which...

Just got my latest power bill... Fuck me.
Never running the heater again. Its ran from an inkbird, only used it for half the Winter billing period, but easily doubled the usual grow cost. I had my suspicions this was coming, hence turning it off mid grow resulting in stunted plants from the cold. The sacrifices we make hey!

What heater were you running mate?

 

[Madmick]

Maybe try 6 on 2 off

Can get 2 cool off period on hot days

Think sooty might use this light schedule in veg in warmer months too

 

[elsooto]

Maybe try 6 on 2 off

Can get 2 cool off period on hot days

Think sooty might use this light schedule in veg in warmer months too

Mate I've been running that schedule for ages now, can't say I'll be changing it anytime soon either. It's a lot more manageable for temps in my space pretty much all year round. You sorted me real good with that tip mic

 

[thefullspectrum]

What heater were you running mate?

A flat panel heater. 450watt Hard to really gauge how much juice it sucked with the house split system heater and the drier running a fair bit.

 

[Porky]

A flat panel heater. 450watt Hard to really gauge how much juice it sucked with the house split system heater and the drier running a fair bit.

Yeah that's massive.
I got 2 greenhouse bar heaters one at 80w and one at 100w give off great heat I used em for a few years in an old uninsulated garage with open eves and they performed great.
Take up fuck all space too!!

 

[Secretchief]

Look up Emerson effect, while not exactly what you are describing it is similar in way of mimicking sunrise and sunset color spectrums to stimulate more photosynthesis

For OP, while unlikely to be an issue, there is a possibility going from 24/0 to 12/12 immediately at flip could be a stressor

End of day effect and Emerson effect are very different (there is alot of confusion amongst forums about this). End of day is just 730nm after lights out, used to reduce required dark cycle and supposedly reduce time to harvest. Emerson is combining 660 + 730 during entire lights on for more efficient photosynthesis. Not sure if we can post links to other forums but riu has a good thread on it.

 

[puggle6]

End of day effect and Emerson effect are very different (there is alot of confusion amongst forums about this). End of day is just 730nm after lights out, used to reduce required dark cycle and supposedly reduce time to harvest. Emerson is combining 660 + 730 during entire lights on for more efficient photosynthesis. Not sure if we can post links to other forums but riu has a good thread on it.

I think you are referring to Red drop which is 700+ nm at end of light cycle which reportedly can extend flowering time etc.

660nm is really only needed for start up if using a full spectrum main light. At least the is the way I understand the science last time I waded through the theory.

Emerson theory has them in combination that triggers the boost, where alone they do not contribute the same increase.

 

[Secretchief]

I think you are referring to Red drop which is 700+ nm at end of light cycle which reportedly can extend flowering time etc.

660nm is really only needed for start up if using a full spectrum main light. At least the is the way I understand the science last time I waded through the theory.

Emerson theory has them in combination that triggers the boost, where alone they do not contribute the same increase.

Mis read a little, you were talking more spectrums and sunrise/sunset.
End of day effect is basically to do with the plant stopping photosynthesis at lights off but taking another few hours to finish the process before it can sleep, the 730 can cut that time to a few minutes giving more efficient use of dark hours (need less). Not sure if that is the same as red drop

 

[puggle6]

Mis read a little, you were talking more spectrums and sunrise/sunset.
End of day effect is basically to do with the plant stopping photosynthesis at lights off but taking another few hours to finish the process before it can sleep, the 730 can cut that time to a few minutes giving more efficient use of dark hours (need less). Not sure if that is the same as red drop

Yes the 730nm is called red drop, as you say turning off photosynthesis whereas normal lights out the plant will still be photosynthesising for up to a few hours later... Which in theory you can stretch lights on time to maybe 13 or 13.5hrs
It's still a part and parcel of the overall Emerson effect

 

[Secretchief]

Yes the 730nm is called red drop, as you say turning off photosynthesis whereas normal lights out the plant will still be photosynthesising for up to a few hours later... Which in theory you can stretch lights on time to maybe 13 or 13.5hrs
It's still a part and parcel of the overall Emerson effect

Up there with uv for me, probably works but better ways to spend your coin. Could have use for people growing sativa or landrace

 

[puggle6]

I'm not sure I would really want to stretch the light hours for just 60-90mins considering the problems it could cause.

Some reported effects seem to be faster and more vigorous trichome production and less time to finish (just for Emerson not extended light cycle) so there seems to be merit in the documentation that's searchable.

If I were to bother I'd be running something like the following.

660 + 730 15mins before and after main light on (to wake the plant up and have the effect triggered)
12hrs of full spectrum light (which includes 660 & 730nm)
730nm 15mins before and after main light out (to put her to sleep)

To be a real rebel you could smash 10k UV for hours 13-13.5 then hit it with the 730nm
(tipping that might end in disaster tho lol)