First Grow, Northern Lights Auto Reluctant to Flower

Hi everyone, new to growing and to the forum. I have a beautiful NL auto going right now from ILGM. The pic is from a few days ago. I am growing it under a 4 tube T5 with two agromax bloom led T5s with 4600 lumens that have full spectrum mixed with red, 1 Hortilux power veg FS+UV t5 bulb and one agromax pure bloom t5. For veg I used two Hortilux FS+UV FL bulbs mixed with two regular FL bulbs that came with the T5 set up. The whole grow is surrounded with Vivosun 6mil diamond mylar with very little light escape. I also have a small fan circulating fresh air through. When we have good sunny days I bring it outside. If not it stays under the lights. I know it’s not the most optimal set up but it’s all I have for now. The plant is in week 6.5. Any ideas why it has not shown any signs of flowering yet. Could it be an accidental regular strain of NL? I have been using Botanicare Pure Blend Pro and CalMag and recently have been adding in some Aurora Soul Peak in per the rec of my local shop. I always air on the side of caution with the nutes since they are autos and have not had a single issue with nute burn yet. I keep a good water cycle and ph balance all of my water and nute additions. I’m a homebrewer so I have a very nice PH meter. I’m running a 18/6 light schedule, average of 72 deg in the house. There is a 2" layer of washed and sterilized play sand on the top to keep the fungus gnats at bay.IMG_6390

Any thoughts on what could be causing this issue would be greatly appreciated!


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The autos will flower when they feel like it. I believe @WickedAle relates growing autos to herding cats. You can try and kick it in gear by switching to a 12/12 schedule


Thanks BD. I did read about the 12/12 approach somewhere, thanks for confirming that. I do also have a smaller Blueberry in there as well. She is showing the first signs of flowering. Would the Blueberry be ok under the 12/12 as well?

Beautiful cats! Autos do great 12/12 from seed so I would not hesitate to flip. Now when they bloom…that’s another question.

I had a white widow auto go close to 3 months before it would flower. I had to drop lights to 12/12 and it still took about 3 weeks before pistols showed

Unless you are really anxious to get it flowering, I would leave it as is for another 1.5 weeks. Every strain and environment is different, but in general most autoflowers seem to start flowering around weeks 6-8. For now, let it take advantage of the light… unless you are in a hurry.

Could just be recessive auto gene, you move them to 12/12 if you want. Both plants should be fine.

@dbrn32 can you flip the lighting cycle to 12-12 on a auto and get them to begin to flower aswell ?

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Also is there a minimum you should let a photo veg for before flipping the lights to 12-12 to start flowering ?

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Ya. They should both flower under 12/12 as long as they’re mature enough. That would be roughly 4-5 weeks old.

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Thanks buddy ! I apologize for hijacking the thread for a moment but @dbrn32 is the light guru of the forum so i needed his knowledge where i fall short .

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Thanks Wicked! I am going to give the 12/12 schedule a shot and report back. That seems to be the general consensus. I will switch the timer to 7am to 7pm so it’s on the same schedule as what we are getting outside incase I bring them out during nice days Thank you everyone for all the suggestions and feedback. This forum is pretty awesome! Have a great weekend everyone.

No problem, good to know.

Make sure you keep the lighting schedule constant in any case. I have seen some plants go wonky when they do see varied daily light schedules even if they are autos.

Is it ok to bring them outside on sunny days and then back inside in the evening under the indoor lights as long as the total light exposure stays at 12/12? Also should the fresh air circulation fan be running when the lights are off or can it be shut off? It looks like the Blueberry is already responding well to the 12/12 schedule. Hopefully the NL will follow.

Thanks Wicked!

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NL doesn’t get huge buds but they are very dense. Yielded 7.6Z from mine 12/12 from seed. Never finished a blueberry but AH gave massive yields.

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Hey dbrn32 I see you know wat you talking about so could you help me out please I have 2cheese autos and one is reluctant to flower the other is in bloom I run them on24/0 light but I’m thinking of flipping to 12/12 will the other plant still yield ok under that cycle?? O there 43 days old.cheers mate

Autos and photos both need to night time to grow. I would not run 24/0. You may get them to flower on 12/12 but autos have their own schedule.

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If you’re not struggling to light your space they should yield fine on 12/12 schedule.

Thanks for replying I’m not struggling no so should be fine