Seedling question is 12/12 lighting ok to start with for autos

Got my auto seeds in today and my 2 plants are about 3 weeks away from harvest. I plan on starting the autos once they pop in their forever homes. Is it ok to start them in my tent while my others are on 12/12 lighting. I only have 2 lights and don’t want to invest in another right now. By age 3 weeks they will have the tent all to them selves.


Try it. You got nothing to lose. Most of us do 24/0 for the first week then 18/6 or 16/8 for a few weeks then 12/12 until harvest. My WW autos are at 16/8 right now and finishing their 3rd week on 6400k CFLs

As soon as my others are ready I will put the autos under 18/6. I guess if I remove a light when it’s time for lights out I could run them under 24 hours of light just by switching one light back and forth. It would be more work but I would rather do that then harm my girls.

Best to move the small ones to more light after the 12/12 lights shut off.

Hard to start new ones when still working an established crop.

Thank you. My plan will be to move one light at the end of the 12 hour cycle and run it over the new plants the other 12 hours. More work but it will be better in the end

ONLY works if the almost harvest ready plants DO NOT GET ANY LIGHT.

I plan to remove the light and put the new girls in a closet to keep all light away from the ones in flower. Thank you for the information. ada226fb052bba3eff0d245a45fcf57051fb778e

You are welcome…

You can do that but it’s totally unnecessary. Autos can be on 12/12 their entire life cycle if u like. I run my autos on whatever schedule I have room for them in. That’s the beauty of autos.

U can switch their light cycle whenever u want as well.

Happy growing


You should be fine to pop your auto seeds and put them in with your flowering plants. The duration of your light cycle will have NO negative effect on your autos. Now, you may not get as much growth with a 12/12 cycle as you would with 24/0 but they’ll be just fine - especially if you’re 2 weeks from harvesting your flowering plants. The Ruderalis in the auto strains basically replaces a light-induced growth schedule (in the plant’s DNA with an alarm clock. The autos know internally, on the day they’re born, when they will begin flowering and when they’ll be ripe. So, they’ll make do with whatever light they have available. They’re not like photosensitive plants that get effected by changes in lighting schedules. As @anon95385719 said, you can grow autos for their entire life cycle at 12/12 and still produce flower. In fact, you could grow them to maturity on 6/18 if you wanted to - but the size and density of the buds would suffer. I’m just reiterating my point here, with that example. If you put your seeds in water today, you’re looking at 4-7 days before they emerge from your medium. That means they’ll only be under the 12/12 for, what, 7-10 days? You won’t see any measurable effect to your final result if you start them now…other than getting your next harvest in 2 weeks earlier. Lol!

If you’re really that worried about it, go get a single T5 fixture and a cool white (6500k if they have it) bulb at Walmart or a hardware store and put your seedlings under it till you harvest your flowering plants. They’re super cheap and will work great for the first couple of week for auto seedlings - they just don’t gobble up much light at that stage. The light in your tent is, actually, largely wasted on seedlings in their early stages. Unless you have a floor full of seedlings, that is.

Hope this helps. Remember, there are very big differences between autos and regular, photosensitive plants. FWIW - I’ve learned a LOT over on about growing autos specifically.


No plant does well on 24-0. Plants need a rest period and during dark is when the most transpiration takes place and the nutes retreat to the roots. If u measure growth in your plants u will find they do the majority of their growing in dark.

I guess we’ll have to agree to disagree. Plenty of growers including commercial growers of auto strains using 24/0. To each their own. :wink::+1:

Sorry but commercial growers don’t grow autos.

What i need to find out is My plants have many flowers from a 12/12 light cycle now they have flowers what do i need to do with the lights some one please help me.

What do I do at this stage?help.

keep growing. looks healthy. needs to grow more