Hey guys lots of good info here. I got purple haze fem seeds from here and sprouted them dec 6th, planted on the 10th of dec. i have a 125w cfl and 4-26w cfls also in there. Lights sitting about 3 inches above plants. This is a pic from today, these plants seem to be growing super slow or something. I have seen other “3week old plants” and they are much bigger. I started feeding ff grow big and they started more leaf production but they are short. Any advice? 
You cannot judge a plants size or vigor against another, unless they are from exactly the same genetics or from clones. Be patient. rots have to form in order for plant to grow. Adding nutrients at this early stage could burn them and is not advised.
Don’t rush the process , in time it will come alive .
I see discoloration in the leaves, not as bright and healthy green as I’d like to see. Also the stems don’t look right. Yes it is purple haze, but it shouldn’t have purple stems like that right off the bat.
What is the pH and nutrient concentration at the roots in EC or PPM?
I think I see nutrient deficiencies and or toxicities as indicated by the purple stems and yellow leaves.
This grow should’ve been finished by now. Unless he vegged for months and months.