Do Autos Need Total Darkness?

Do autos need total darkness to switch to flower?

My plant sits about 10 feet from my screened porch. I have 2 strings of LED Christmas lights that line the inside rim of the porch “inside” and hanging party lights about 20 feet away.

My do-si-dos auto flower is well past the age to flower I think. I don’t see any pre flower, buds etc. I “think” my plant is 10 weeks old? I use Jacks and the plant is growing rapidly.

Curious if the nearby LED lights are having a negative impact.

Guess I’ll turn them off a while to see. Curious what you think


Auto’s do not need total darkness to switch, my guess is, you have a photo plant. I would eliminate ALL the lights for now. I run photo’s outdoors and I turn all my outside lights off. :v:

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Thanks for the reply. I wondered if it was photo instead of auto. My first grow so I don’t know. Got the seeds from ILGM so I’d like to think they sent the correct seeds.

I’ll continue to feed and see where it goes. Nothing to lose.

I’ll also set
My light time to kick off after an hour or so


Growing outside I would go with the normal light cycle and eliminate the extra bulbs. I have seen a street light cause a photo plant to (hermie)
Good luck :v:


No, they don’t require absolute darkness to flower.
The best way to tell if a light is effecting the plant is with a light meter app using the DLI setting.
Our eyes are better gatherers of light than the leaves of a plant are believe it or not!
So just because you can see it DOESN’T mean it’s effecting the plant.
My under-cabinet LEDs in my kitchen burn all night long and shone onto my outside deck plants about 20-25ft away. When I step outside and let my eyes adjust the closest plant looks like she’s in the spotlight for her solo dance number. But when I put the DLI meter right at her leaf surface area on that side of the plant it gives a ZERO reading. This means that the light energy reaching the surface of the plant IS NOT strong enough to effect the plant. It’s doesn’t even see it at all. As far as she knows she IS in total darkness since the lights energy isn’t enough to trigger ANY response in her at all.
Now if you get a reading, any level of reading at the leaf surface then she IS seeing the light and it IS having an effect - most likely detrimental as described by @kellydans .
Although light exposure isn’t the only factor in causing a herm and it’s actually debatable if it has anything to do with herming as plants in tents that get zero light exposure in the dark period will also herm. Genetics play the biggest part in whether a plant herms or not.
One way or the other, if that “needle” moves then the light IS strong enough to cause activity in the plant.
Break out the phone app and test away - that will tell the tale.


Any light reading can also delay flower as well. Like @Tylersays said you can check your dli, if you have anything you need to eliminate the light source. I’m also 1 that doesn’t like any light as well. :v:


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Im sure whatever the problem is, it’s something I did. First grow mistakes.

My main concern was the lights at night. Im gonna keep fertilizing and will turn off my lights for a while and we how it goes.


Oh don’t blame yourself here, if it was a “true auto” it would have bloomed before that, people run lights 24/7 on them and they flower.

Even if it’s claimed to be an “auto” seed, it could be taking after some other part of its genetic heritage and ignoring the “auto” genes.

I had one that took “forever” to flower, it was at 44 days though so you’re well over that mark. The rest started between 16 - 28 days.

Good luck!


Cross fingers I haven’t had a hermie yet outdoors. We have a lot of light pollution here especially with the increase in crime and the neighborhood adding security lights and motion activated lights to their yards.

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Curious about that myself. Have a Maui waui auto a friend gave me 4 months ago. Dang thing is 6 ft tall and still hasn’t shown a single flower in 4 months.

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