I'm growing some indoor autos in airpots in a mix of moss peat ( pH 5.5-6.5), perlite, vegetal compost + soil amendaments such as bat guano and bananna peel powder. Could you tell me how bananna peel powder and bat guano affects the pH of substrate?
No doesn't work that way. As Jack said do a slurry test before growing or you will have a rough go.
I suggest a premixed soil if your not familiar with amending soils. It's not that you can't mix your own just if you fuck it up it's going to cause lots of issues during the grow.
That or do a whole lot of research before you do and make sure you fully understand how soil pH works.