First of all, are you growing with hydro ? if so get a TDS meter and adjust your nutes according to this chart. Notice that ppm for seedling is 100 to 250ppm, I find that hard to maintain 'cause my water is 185ppm. maybe buy bottle water for you seedling. This is just a starting point, you may have to adjust acording to your strain. if soil, maybe someone else can help, I'm a hydro man.
Seedlings, Early Sprouts ..100 to 250
Early Vegging ......................300 to 400
Full Vegetation ....................450 to 700
Early Blooming ...................750 to 950
Full Mature Blooms ...........1000 to 1600