You have not put any information about the light's feed grow medium nothing this make's thing's realy hard to answer yr question.But i know what light's you are useing from the little bit of info you have put,you are useing flouresent's i would say.If you was useing h.p.s/h.i.d lighting then the plant's would be around 1ft to 1/1/2 ft tall after 4 weeks of vegging with loads of side growth.I may sound has though i'm been a little harsh in what i put now but if you are gonna use flouresents be cfl's or tube's just get rid.These kind of light's are a waste of time,they will produce very little in the way of the end result[bud].H.p.s light's are not too exspensive to buy now.Look into getting a hps light pref a 600 if used in a large room then you will only need a ossalateing fan to blow across the top of the plant's.But if useing a hps/hid light in a small area then a exaust fan will be needed use this in conjunction with a carbon filter and a cool hood not cool tube,cool tube's take away valuble luman's where has a hood take away none,well maybe a little.I used a cool tube for a few grow's and since swopping over to the hood my yeild has increased by 30%.But the most important thing is that you do not give up if the seedling's taht you have a female then leave them on 18/6 till you get the money for the up graded lighting.The reason that i say this is you can keep the flouresents for mothers and clone's but you will need to add more tubes so your mothers are getting good lighting and you will inturn get more good genetic stock.Keep at it tyke and question's post me stay green peace.