Most strains I feed at 1.4 from day one to week 6 of flower. 1 in 10 strains prefers 1.2 (amnesia) or 1.6 (chemdog)
3ml/l for.4 EC of Start
Veg 1.25 ml/l to 1.75 ml/l ( .6 EC to .9 EC) A/B
Flower 1.75 ml/l to 2.25 ml/l (.9 EC to 1.2 EC) A/B
1.5 ml/l PK 13/4 (.4 EC) and 1.5 ml/l A/B @ midflower for 6 days
Optimal EC/PPM for Veg is determined by the type media and method you are growing with. What type growing media are you in?