Northern Lights Seeds

What Light Cycle to Use for Northern Lights Autoflower?

Alright, so you’ve got your hands on some Northern Lights autoflower seeds—nice. Classic strain. Chill high. Smells like pine and dreams. But now you’re staring at your grow setup, wondering what kind of light cycle to run. 18/6? 20/4? Full 24/0? People argue about this like it’s religion.

Let me just say this straight: autoflowers don’t give a damn about your light schedule the way photoperiods do. They’re on their own internal clock. You could run 24 hours of light and they’ll still flower when they feel like it. That said... doesn’t mean light schedule doesn’t matter. It does. Just differently.

I’ve run Northern Lights autos under all three—18/6, 20/4, 24/0. Each has its own vibe. 18/6 is the most balanced. Plants get a rest, your electric bill doesn’t scream, and you still get solid growth. It’s the “safe bet” schedule. If you’re new or just want to keep things simple, go with that. It works. No drama.

But if you’re chasing yield—like, really trying to squeeze every gram out of those sticky little bushes—20/4 or even 24/0 might be your jam. More light = more photosynthesis = more energy = bigger buds. That’s the theory. And yeah, it tracks. I’ve seen chunkier colas under 20/4 compared to 18/6. Not night and day, but noticeable.

Now, 24/0... that’s the all-gas-no-brakes approach. Some growers swear by it. Say their plants love it. Never sleep, just grow. Personally? I think it’s a bit much. Plants are living things, man. Even autos. They need a breather. Constant light feels unnatural. Like feeding someone espresso intravenously. Sure, they’ll get stuff done—but at what cost?

Also, heat. If your setup runs hot, 24/0 can cook your tent. Especially in summer. Don’t underestimate that. Lights on all the time = no cool-off period. Your roots might start sweating. Not good.

So here’s what I’d do if I were you: start with 18/6. Let the plant show you what it wants. If it’s stretching too much or looking sluggish, bump it to 20/4. See how it reacts. Don’t just set it and forget it—watch the leaves, the color, the posture. They’ll tell you stuff. Plants are weirdly expressive if you pay attention.

One more thing—Northern Lights is a chill strain. It’s not some diva that needs a perfect environment. It’s forgiving. You can mess up a little and still get decent buds. That’s why it’s a favorite for beginners. So don’t overthink the light cycle too hard. Just pick one, stick with it, and focus on the basics: airflow, water, nutrients, love. Yeah, love. Don’t laugh.

Anyway, that’s my two cents. You’ll find your rhythm. Just don’t let Reddit threads convince you there’s only one “correct” way. There isn’t. Plants don’t read forums.