Light cycle for autoflowers

Natronastarted grow question 1mo ago

Can autoflower plants thrive in 12/12 light cycle? Will this extend the veg and then the flower phase? My Grow box resets to 12/12. I grow autos at 18/6.

Solved

likes

MadProfessoranswered grow question 1mo ago

Some options: 1. Use fast-finishing autos or small strains (e.g. FastBuds, Sweet Seeds, Mephisto genetics — compact plants do okay even with less light). 2. Boost DLI (Daily Light Integral) Run your LEDs at higher intensity during the 12 hours (if temps allow). Example: raise PPFD from 600 → 900 µmol/m²/s to compensate a bit for shorter days. 3. Keep environmental conditions perfect Temps 25–28 °C CO₂ ~400–800 ppm (normal air is fine) High root health (microbes, balanced watering) 4. Accept slightly lower yield, but good quality Autos under 12/12 still produce solid, resinous buds — just smaller plants. If your grow box can’t change cycles, you can absolutely still run autos — just expect them to stay smaller and focus on maximizing light intensity, nutrients, and environment to make up for shorter days. Big up and keep growing greeni green 💚🙏

2 likes

Complain

Selected By The Grower

m0useanswered grow question 1mo ago

1) water the entire pot. don't leave dry spots in the center it can fuck you later. 2) if the DLI for 12/12 is the same as 18/6 then it should preform about the same. I don't think it gives you any advantage of more veg time or anything. If anything it might speed it up as increased darkness help make plant flowering hormones in photoperiods, but from my limited understanding, autos are not affected like that. But I could be wrong.

1 like

Complain

Selkotanswered grow question 1mo ago

hey 👋 Unless you are growing autoflowering plants at the same time as photoperiod plants in the same tent, which would justify 12/12, give your plants an 18/6 cycle. This means you don't need to run your lights at full power, risking overheating and burns during the day, and a nighttime period that is too cool and too humid. Ruderalis genetics are different from indica and sativa, converting energy into sugars more quickly and spreading their roots less (two processes that take place at night). What you would save on your electricity bill, you would lose in yield 😉

1 like

Complain

Ultravioletanswered grow question 1mo ago

Yes, my diary chapter #12 was 4x auto at 12 hours for entire grow. You would need to increase intensity though to compensate for the loss of time.

1 like

Complain

Nocone_Purpleanswered grow question 1mo ago

Autoflowers can grow and flower under 12/12, but they won’t reach their full potential. They don’t depend on the light cycle to start flowering, but less light means less energy for growth and smaller yields. Best results come with 18/6 or even 20/4

1 like

Complain

00110001001001111Oanswered grow question 1mo ago

As long as you give the same DLI over 12h that you did over 18h there should be little difference in yield. This is certain. I doubt it impacts an autoflower's mechanism for when it enters flower phase. This is likely but not 100% certain. Autoflowers are fickle things. Treat them poorly and it might induce or delay flower. I don't know exactly how the autoflower plant triggers flower, but it's definitely not a hormone that is produced in the dark...

1 like

Complain