Purple Punch x Do si dos

thanks for this. i was actually going to get these seeds from philosopher but i could not find a bank that shipped to the usa. i ended up getting purple dosi punch photo seeds made by growers choice sold on seed city. i'm on week 3 day 16. this is my first photoperiod grow. not sure how long i should let them veg for. my tent is 4x4x7.5. looking at yours i might let them veg until they are like 15-20 inches...