when do you know its time to flower

i was wondering when do you know when to flower or do you just switch to 12/12 and automatic flowering?

i flower when plants are about 12'' tall

you can start flowering whenever ud like really just depend on how big u want them i no ppl that have veg for like 3 months indoors then flowered depends on ur paitence to i guess u can flower right from clone. i veg my plants for a month then induce flowering and thats what ive been doing for my last 4 crops and it has worked fine the plants end up being about 5 feet when its all said an done. it also depends on the watts that u are using the more watts the bigger the plants and buds depending on how many plants and space.

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