18/6 VS 24/0 Light schedule for Autos

18/6 or 24/0 light schedule for autos?

  • Total voters
    13
C

CincityFinesse

Active Member
18/6 Pros

  • For hot climates, the ability to turn off lights during 6 hottest hours of the day
  • Uses 25% less electricity than 24 hours of light a day (which adds up if you have expensive electricity)
  • Plants are harder to stress and recover faster from problems. Often the grow light can be kept closer. This extra hardiness can make things a little easier for you if you run into problems, or if it’s your first grow.


  • 24/0 Pros
    • Cannabis plants typically grow faster when they get 24 hours light/day, especially during the first month of life.
    • A good choice if it gets cold and you don’t want lights to turn off! Keeping the lights on 24 hours a day can prevent the grow space from getting as cold at night
    • If plants are very healthy and growing fast, it doesn’t matter if they’re more resistant to problems
 
twentyeight.threefive

twentyeight.threefive

Well-Known Member
I've vegged autos on 18/6 and 24/0. With a strong non-adjustable LED light my 24/0 autos were stressed. Another pair vegged under 24/0 blurple turned out great.

I've got a current group of 4 autos vegged 18/6 and they are now flowering and looking fantastic. Best group yet.
 
C

CincityFinesse

Active Member
rkymtnman said:
never said they were wrong. i like thc: the more the better.
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There are autos with really high thc content. Just bc one strain is higher in PP doesn’t mean they all are. Autos are better in a lot of ways and are the future of cannabis. Plus u can’t beat 2-3mo harvest. But this wasn’t a autos vs PP thread, it was a 18/6 vs 24/0 for autos. Stop hating on autos!
 
P

piratebug

Well-Known Member
I like using 17/7, as there are very few places in this world where 17+ hours of natural light shine in a single day, and in not one of those places has a single cannabis strain ever naturally evolved. All cannabis strains have evolved in regions where they naturally vegetate for between roughly 12 hours and 45 minutes at the equator, to 16 hours and 35 minutes in the northern, and southern hemispheres. And you can literally see that in a controlled environment, because every cannabis strain will clearly tell you when its had enough hours of continuous light no matter how much more light you may want to give it in a 24 hour period!
 
Star Dog

Star Dog

Well-Known Member
piratebug said:
I like using 17/7, as there are very few places in this world where 17+ hours of natural light shine in a single day, and in not one of those places has a single cannabis strain ever naturally evolved. All cannabis strains have evolved in regions where they naturally vegetate for between roughly 12 hours and 45 minutes at the equator, to 16 hours and 35 minutes in the northern, and southern hemispheres. And you can literally see that in a controlled environment, because every cannabis strain will clearly tell you when its had enough hours of continuous light no matter how much more light you may want to give it in a 24 hour period!
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I've grown many strains under 24hrs light and they love it, rudiralis afaik the key gene in autos originate from Alaska where it's 24hrs of light in the growing season?
 
C

CincityFinesse

Active Member
Blazin Budz said:
Seems like you have a lot to learn. Grow out some NightOwl, RocBud or Mephisto strains and then form an opinion. People seem to be stuck in their old ways. BTW I grow both.

To answer your question OP. It's generally considered that 20/4 is an ideal light cycle for autos.
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I’m using 42 fast buds, and boy the name doesn’t disappoint. I can’t believe they really tried to hate on autos like that. Do u have experience with the different light schedules to compare yields?
 
C

CincityFinesse

Active Member
piratebug said:
I like using 17/7, as there are very few places in this world where 17+ hours of natural light shine in a single day, and in not one of those places has a single cannabis strain ever naturally evolved. All cannabis strains have evolved in regions where they naturally vegetate for between roughly 12 hours and 45 minutes at the equator, to 16 hours and 35 minutes in the northern, and southern hemispheres. And you can literally see that in a controlled environment, because every cannabis strain will clearly tell you when its had enough hours of continuous light no matter how much more light you may want to give it in a 24 hour period!
Click to expand...
What results have u seen growing 17/7 compared to the other ones?
 
C

CincityFinesse

Active Member
Star Dog said:
I've grown many strains under 24hrs light and they love it, rudiralis afaik the key gene in autos originate from Alaska where it's 24hrs of light in the growing season?
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That’s what I was thinking, more light = more energy = more growth. But what do I know I’m a beginner with big ambitions. Have u tried other light schedules or just the 24/0? I really want to compare ppls results.
 
BloomFielder

BloomFielder

Well-Known Member
CincityFinesse said:
18/6 Pros

  • For hot climates, the ability to turn off lights during 6 hottest hours of the day
  • Uses 25% less electricity than 24 hours of light a day (which adds up if you have expensive electricity)
  • Plants are harder to stress and recover faster from problems. Often the grow light can be kept closer. This extra hardiness can make things a little easier for you if you run into problems, or if it’s your first grow.


  • 24/0 Pros
    • Cannabis plants typically grow faster when they get 24 hours light/day, especially during the first month of life.
    • A good choice if it gets cold and you don’t want lights to turn off! Keeping the lights on 24 hours a day can prevent the grow space from getting as cold at night
    • If plants are very healthy and growing fast, it doesn’t matter if they’re more resistant to problems
Click to expand...
Spot on.
 
calvin.m16

calvin.m16

Well-Known Member
18/6 otherwise you're just wasting electricity and not giving your equipment or plants any rest. I've flowered autos under 16/8 12/12 and 18/6. Any of those time frames will work although 18/6 will give you the best yields with most autos.

Why grow autoflowers anyways? I cant stand them, I grew several varieties and found it pointless and went back to photoperiods that I can clone and not need to buy or source seeds and have inconsistent results.
 
C

CincityFinesse

Active Member
calvin.m16 said:
18/6 otherwise you're just wasting electricity and not giving your equipment or plants any rest. I've flowered autos under 16/8 12/12 and 18/6. Any of those time frames will work although 18/6 will give you the best yields with most autos.

Why grow autoflowers anyways? I cant stand them, I grew several varieties and found it pointless and went back to photoperiods that I can clone and not need to buy or source seeds and have inconsistent results.
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Have u grown PPs and autos along side each other 12/12? How did the autos turn out? 18/6 is recommended and I’ve read 12/12 can really effect yield in autos, but u can do it.

Autos grow extremely fast. In the time it takes to grow one photo u can grow two autos and get a better yield. Only thing with autos is u can’t control flowering. Fast and effective.
 
C

CincityFinesse

Active Member
twentyeight.threefive said:
I've vegged autos on 18/6 and 24/0. With a strong non-adjustable LED light my 24/0 autos were stressed. Another pair vegged under 24/0 blurple turned out great.

I've got a current group of 4 autos vegged 18/6 and they are now flowering and looking fantastic. Best group yet.
Click to expand...
I have a led with dimmer samsung diodes and meanwell driver, currently have seedlings on 18/6 but I’m leaning towards trying 24/0 for first month. Do u think yours would have turned out different if u had a dimmer in your led?
 
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