What light schedule to give Auto Flowering plants


What type of light schedule should I give my auto flowering plants? I’m running LEDs.


Just me everything ive seen 12 and 12 make it mature faster. Then figure out if you can adjust the light to last a couple more weeks then normal. They will yield more.


Thank you. Do you start 12 and 12 from the beginning ? Even when starting seeds?


From what i have learned. It seems to do the best. It looked to mature faster. I think it grows better because of its natural instinct to grow at that cycle.


Remember the faster it matures which autoflowering plants depend on maturity not light cycle. But it natural instinct to grow flower will always be 12 on 12 off. So the question about from seeding is a judgement call.


Thank you this has been very helpful!


I am somewhat a beginner myself but it is my understanding you should give seeds/seedlings a lower intensity light 24/7 until they get a couple inches tall…then graduate them to higher intensity light at 12/12…then adjust lighting schedule to 20/4 until flowering… when in flowering gradually adjust the light schedule back to something like 10/14


With autoflowering cannabis 18-6 the whole way if you want less intense light raise your lights the only reason i use 12/12 would be having a non-auto in flower in same tent thats what im dealing with now

as can be seen shes doing great on 12/12 but it can hurt your yield


do you run 18-6 for seedlings also ?


Wait for a set of true leaves the go to town thats what i did then over time lower light down as she grows then at a point shell start working her way to the light raise up little at a time to keep her from streching


“I am somewhat a beginner myself but it is my understanding you should give seeds/seedlings a lower intensity light 24/7 until they get a couple inches tall”

Many people do this, but it’s not a necessity.

“then graduate them to higher intensity light at 12/12”

Most people veg plants anywhere from 18 / 6 to 24 / 7

Autoflowers are started and kept at something at or above 18/6

The only time 12/12 is used is to induce flowering in photo period plants
-good luck

“then adjust lighting schedule to 20/4 until flowering… when in flowering gradually adjust the light schedule back to something like 10/14”


Thanks Norman,…been working it out as I go,lol…have not grown since 83 so lots has changed since then… trying to study up before I spend my money on equipment


@Oak Same here, I started in the mid-eighties and quit in 95. I just started again five months ago

Here is a thread of what I did from bare floor to now, including equipment recommendations, what to do, what not to do, plenty of mistakes and some success as well :thumbsup:

-good luck and if I can answer any questions just ask ?

By the way, it’s kind of like riding a bike :wink:


Thanks Norm… I read that thread a couple days ago…good stuff! I lurked around the forums a couple days before I joined…lots of good info available here.
I am in the very beginning stages of my growing. I have zero equipment, lol… not sure how the ol’lady is going to react as I have not discussed it with her yet. Gonna have to soon though as I am disabled as well, but not yet on disability…just starting the medical BS for that now…so I have zero income at the moment and have been a house hubby for the past couple of years. She pinches the pennies pretty tight so that may limit my start up ability. I have ordered seeds though… I ordered 10 WW autos from ILGM and five “Amphetamine” auto from Seed Supreme… split my order to try and increase my odds of getting some magic beans without getting screwed out of all my money,lol… that amphetamine is basically a NYC Diesel auto from what I gather…all these funny names these days trip me out… I would still bet money that Mexican dirt weed is still the #1 seller back in California, lol. I am in the American deep south now, along the gulf coast…so I need to find a few strains that do well with heat and high humidity…figured starting with autos would be best…get a few easy grows out of the way so I have some nerve calmer available when shit starts getting stressful,lol.


I hear you man I’m all in for about 1500 bucks everything totaled that’s about a Year’s worth of weed at the dispensaries around here and there weed sucks

If you have the option of growing outside you’ll save money, much easier too in my opinion …that’s just nature doing what she !



First I would like to Welcome you to ILGM. There is a wealth of information here in our forum. And all the fokes here are more than ready to help as you can see all ready.

Anyway here ya go. If you need any more info on this light schedule just let me know. I got plenty on this subject

Most growers seem to agree that the optimum amount of light to give auto-flowering strains of marijuana is somewhere between 18-24 hours of light a day. When I’ve grown auto-flower plants, I gave them 18 hours of light a day, and 6 hours dark, at least partially because it allowed me to turn the grow lights off during the 6 hottest hours of the day (I live in East Tenn where it’s hot and the humidity is high most of the summer

Recommended: 18-24 hours of a light a day

I’ve also seen many great growers give their autos 20, 22 or even 24 hours of light a day.



Perfect thank you!! What do you recommend for lighting for seedlings?



Light cycle: Keep it between 18 – 20 hours of light per day from start to finish.
Don’t jump around, if you begin a 18/6 or 20/4 keep it there for the whole grow.
Running the lights 24/24 is a waste of resources IMHO, and not healthy for the plant (though there are those who dispute this). Over pushing ANYTHING will reach a point of diminishing returns, just as doint the opposite; switching light cycles down to twelve hours will diminish the potential yield of autoflowering marijuana strains.
I like to spread out my germinations by every 3 weeks or so, to stagger my harvests. Often auto-flower seedlings will start off slowly or small, not to worry, as usually by week 3 they declare sex, begin to bloom and it is usually the following week the growth explodes.



So very true my five week old auto is growing like crazy


Do you have the seeds going yet Oak?