Botanicare : Product Overview : Nutrients

Try this page it tell you all how much for each stage of growth. If you want to add more stay with the same company of nutes. They are listed here.

As far as strains you know widow takes 11 to 12 weeks to finish flower. The afgan/mazar maybe 8 weeks to flower. I would go with the amout listed unless you see tips of leaves burning, then back off some.