When and how to fertilize

hello all, this is my first grow and I need some advice,,,everything is going good so far, I just transplanted them to thier final spots 3 days ago....when should I start fertilzing them? which fert should I use? 4 plants are autoflowering white widow and they have begun to flower....thanks all help is appreciated

i have the same prob put some early has[plant outdoors and they triggered , have had them on N and 24 7 light and they wont go back fat as hell but only 10 inches tall.

ummmm ok you must totally baked,,,,wish i was