Can I go from 12/12 to 18/6?

Discussion in 'General Marijuana Growing' started by matticus408, Dec 15, 2016.


    matticus408 Well-Known Member

    I'm about 2 out from a harvest and want to get a jump on the next grow. Can I sprout some seeds and place them under the 12/12 lights for about 2 weeks then switch the newly sprouted plants to 18/6 after I harvest the current batch?

    I'm afraid exposing them to a couple weeks of 12/12 then the rest of their veg. stage to 18/6 will stress them or kill them.

    Any advice/comments welcome
    vostok likes this.

    GreenSanta Well-Known Member

    you could keep them in 12/12 all the way until they show sex if you plan to veg them for a while they might need a week to go back from flower to veg but if the timing is right you have a good plan. In fact, I always sex my plants in the flower room so I always grow 12/12 from seed until they show sex, then I top them and move them to the veg room under 24 hours.

    GrowinRIte Member

    Yes you COULD have them in there and keep them in there until they show sex and then switch them back. Not too sure a 12/12 light cycle would give your seedlings the light they need to fully develop at a decent rate and not too sure how such a young plant would handle that kind of stress from going from veg to flower to veg. Might be shooting yourself in the foot. Instead you are probably better off ( if you can) build a little box or hang a little t5 outside of your flower room to give them a good jumpstart. Just my 2 ¢

    rkymtnman Well-Known Member

    it might work but the problem you'll have is they'll be stretchy as hell. if it were me, start and keep them under 24/0 and then move them in the tent after harvest
    Bareback likes this.

    vostok Well-Known Member

    I have done this but on returning to 18/6 some strains show signs of stress

    (whorled phyloxy) twisted new growth and can be difficult to fix

    I believe its strain specific so be cautious

    my white widows and skunk hazes all stressed out

    good luck

    GreenSanta Well-Known Member

    what makes you think the plants will be stretchy? my seedlings are litteraly 5 feet from the light and grow very short and start to bush out as they show sex.
    you are right, some strain will grow some twisted leaves as they revert but that is mostly if you dont catch their sex right away.

    Honestly guys the OP was just asking if he could do it for 2 weeks. The plants wont show sex for about 30 days from seeds so there will be no stress whatsoever going from 12/12 to 18/6 at week 2. Furthermore, if you do wait until they show sex (look daily when they are close) and you top them once they do, about 90% of them will have no signs of stress whatsoever.

    I do it all the time that's how I grow, and you guys still argue that it might not work lol, what do I need to do now post pictures of the dank I grow so you understand?

    ThatCrispyKid Member


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