I'm not sure what I'm going to do is sufficient, but I have the ingredients for a seed starting mix composed of peat and perlite.

I realize this isn't ideal for any nutrients with just the two ingredients, but I have azomite, greensand, and other trace mineral compounds I can add to supplement.

But how can I ensure there's enough nutrients to take my seedlings to the "transplanting to the garden stage"? I suppose nitrogen is really the main thing at this stage. But my concern is say fish emulsion: safe to use indoors??

Thanks for your advice! Looking to use what I have this year.