Auto Flowering

After how many weeks should I put my babies under HPS

it depends on alotta crap bro...how much grow space you have, expected yield, training method (if any), cloning plans, etc...you gotta be a little more specific than that

depends on how good of a grower you are really. but by the third or 4th node they should be looking ready. what do you have them under now and how old are they? you can use the hps right off the bat as long as you keep it high enough. i wouldnt suggest it but you can.