wtf is going on ?

a good friend of mine has asked for help he has 4 feminised plants growing all germinated at same time but since he put them in his nft system one has out grown the others by miles there approx 5 weeks old and been in the system for 2 weeks could the smaller ones be stunted,or just slow growing they have good roots and decent stems and pleny of leaves but there so small the tall one is 18inch the others are 9 and 6inch what can i do ? he was thinking of just flowering them cause he dont have a great deal of height also if he does flower will the small ones stay the same height,pls help hes starting to panic,set up is 400watt hps nft system constant flow 18hrs of light and temp around 82 also feeding hydro vega.

Dont panic dude, at 5 weeks you can turn em to flower, the small ones will probably treble in size, if the bigger one looks like it might be too tall, train the colas to grow diagonally. good luck dude.

Like he said ^^^ Feminized seeds tend not to be very stable genetically speaking, so there can be quite a bit of variation between plants. Nothing to worry about. They look healthy.

cheers guys for responses,just started to flower them