some strains only have 3-4 blade leaves in veg naturally. my favorite strain to grow, master kush, never has more than 4 blade leaves in veg(sometimes only 1-2 or 3 blades) but 5-7 blade leaves start to show the 1st 2weeks of 12/12. just genetics i guess as the veg temps are 75-78 using 8 4ft agrosun flouros with a 465cfm squirrell cage for ventillation. it is the only strain i've had that does this.