When to do 12/12

[tk86high]

So I was wondering if I could do the 12/12 at 3 weeks old ?

Reason be is I have a 6 week old in there that is ready to start flowering and honestly she is getting to big as it is now.
And I want to switch the bulb to HPS to get max in budding since its MH right now.

Thanks

 

[Prfectlysober]

3 weeks from seed? or has it been vegging for 3 weeks? if its been vegging 3 weeks it sounds fine if the 6 week one is already getting too big. You could go another week though, and then maybe start flowering continuing with your MH for a week or two into flowering, it will help your plants keep from stretching too much, just an idea.

 

[tk86high]

3 weeks from seed.
just was wondering what r the pros and cons if i switch to 12/12 now ?

 

[Keith Lake]

You can actually run 12/12 straight from seed if you want. Some people do this to shorten the cycle and net more grows per year from their available space.

Earlier switches mean less total weight at harvest.

If you've got another plant that's already too big, you heed to be aware that many strains grow 2-3 times taller when flowered. Plan for LST or other tie off strategy if you don't have the headroom

 

[Jimmycricket]

either way you will want to LST the bigger plant so that they are both equal in height.