Can anyone help?

I have three Northern Light plants that have been grown from seed. Now they are three months old (planted on January 2nd 2007).
This is my first grow have got just about everything I could wrong! Lighting, ventilation, over and under watering and nutes!
They have only recently started to look more mature as I changed to CFL three weeks ago and and added a ventilation fan and correct nutes and water one week ago. They are now eight inches high!
Considering that when would it be best to flower? I will be changing from CFL to 1x400 watt sodium . They are in coco fibre and fed on coco A and B and sprayed with formulex once a week? Also I have recently changed from 24 hours of light to 18/6.

Any ideas guys?

Depends on space, Your plant will hopefully double in size during flower so take size in to consideration before those sticky buds hit the ceiling.

get your girls in order before you even think about harvests. the only thing better than some dank nugs is even MORE dank nugs.