Auto Question from Familyman

So, I’m getting anxious to start my auto grow and was wondering if they will grow normally under a 12/12 schedule. I know they do their own thing but didn’t want to force them into flower too soon.


i think they flower asap for their genetics. Im not sure you can make them flower early or late.

12/12 would be fine. Most go with a 14/10 or 16/8.

I grow auto’s and most will start to show sex about 28 days regardless of light schedule.
But in those 28+/- days, you want as much growth as you can get, or most do.
I recommend, unless it economic or stealth reasons, bump your lights up a few hours until they start to flower in earnest at about week 6-7.

Best of luck @Familyman



A common question I see is when to switch autos from veg to bloom. Many people are under the impression that as soon as they see the first flowers it’s time to switch. Perhaps a little explanation of the life cycle of autos will help to clarify this.

Weeks 1 - 3. Once you’ve started your seeds and they break the surface of the soil, they are in their seedling stage. The first set of leaves to appear will usually single fingered, followed by a second set that may still be single fingered or perhaps 3 fingered. Once that second set appears growth will start to accelerate as the new leaves provide more photosynthesis. This process will continue, more new leaves, faster growth. Depending on the type of soil in use, mild vegetative nutes can be introduced at week 2. By week 3 most plants will start to show their sex. Males will start to produce pollen sacks and females will display pistils.

Weeks 4 - 6. The plants are now entering a pre flowering stage. During this time the plants should exhibit explosive growth, often as much as a new set of nodes and 1" vertical growth a day. This is the time when they will gain most of their vertical height. Many people make the mistake of switching from vegetative to flowering nutrients at this point, assuming that since they see flowers it must be the proper time. This is incorrect. If the switch to flowering nutes is made at this time the vertical growth will stop and the plant will put it’s energy into producing buds. If you need to keep your plants small, or want them to finish earlier, they by all means switch nutes at this point. But if you want to get the most out of your plants continue feeding vegetative nutes until you see the vertical growth slow and stop. Depending on the strain that will usually be sometime during week 5 or 6.

Weeks 7 - 9. By now vertical growth has stopped and the switch to flowering nutrients has been made. The buds will start to fill out and put on weight, becoming hard and tight. Pistols will start to change from white to brown, orange, red, etc. By now the plants will also have developed a strong smell. Toward the end of this phase the large primary and smaller secondary fan leaves will begin to turn yellow. This is an indication that the plant is moving toward the end of it’s life.

Weeks 10 - 11. At this time flowering nutes should be discontinued and only plain pHed water fed to flush the remaining nutrients from the soil and improve the taste. Yellowing of the fan leaves will continue as the plant draws the stored energy from them. Eventually they will die and fall off. By the time that the smaller leaves that come from out of the buds will also start to turn yellow. Then it’s time to harvest.

I know that many of you are thinking that the seed bank said the plants will finish in 8-9 weeks, so why are you saying they take 10-11? The claims made by the seed banks are somewhat deceptive. If you switch to flowering nutes at week 3 or 4 the plants can finish in the times the seed banks say but they will remain small and not reach their full potential yield. Years of growing by myself and others has shown that autos do best if you follow this time line.

Of course, there will always be variations depending on the strain, the environment, nutrients, etc. This information is meant to only serve as a general guideline.


Thank @Screwauger. I’m waiting on these photos to finish and am getting impatient. I’ll just wait until the lights are available or… I could always set up another set :thinking:

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I have a habit of going overboard on things.


Mate are you saying 16/8 light cycle for the full life cycle of an auto would produce the maximum yields or could you go to 12/12 on flower cycle (thus save a bit on running cost) and achieve similar results ? .


I’m no expert but I really don’t think it makes much difference. 12/12 would be fine. I’ve actually ready grows where folks ran their lights 10 on and 14 off and they think that works best. It’s all up to preference (and expenses). Good luck.

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