What week should I start adding veg nutrients?

I advice you against following a set schedule, because it depends on many factors: how much light you have, how much soil you are using, how "hot" or charged is your soil, etc. Learning all this is what is called dialing you system. What I do and advice you to do is to let the plant feed itself from the soil and when you notice that the first signs of deficiency appear, then you start feeding. In my case 11 liter (3 gallon) of soil lasts me 8 weeks usually before needing aditional external feeding. Sorry not benn able to give you a more direct answer, but I think this is the best advice, good luck