adivize a new indoor grower

Hi,
I'm a seasoned toker but new grower.
I've two babes in the closet. been growing for nearly 5 weeks. They're o.k. I'm wondering when to drop the light to 12/12.
The seeds say 9weeks from germination.
I've read you should induce flowering when about 12-16" tall.
I'm about to induce flowering this week.
So, is it right they take about 3 weeks flowering and grow another 3"

Any advice most welcome. this is my first post, but i've been following the seasoned growers pearls of wisdom for a while.
Cheers:wtf:

seems like your seeds mean they take 9 weeks of flowering to be ready, most likely. So whenever you do switch to 12/12 lighting is when the timer starts counting. From whatever size they are when switching to flower, they can grow double that size, depenndent on strain and care.

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