I have been wanting to use bone meal and other organic additives but there is no guide to ratio.

Is it a few table spoons to a 25L bag of soil or is it the whole box of bone meal?

I'm by no means cheap on my supplies I just have to drive a long way to get them and am looking for DIY solutions.

Stinky, what ratio do I use to a bag of soil?
I use a peat based soil with 2/3 bag of perlite to one bag of soil. Botanicare nutes beginning to end.