I do not trust any fertilizer you can buy anymore or get free even if it is labeled organic. I do trust coco coir and fish emulsion. It is best to make your own compost and that way you know it is safe. There are certain brands I trust such as Pro Mix

A lot of people have the same concerns, Amen!!

What Native Americans use is their Farming Secrets, but I can only tell the closest thing I have used in the place of Native Americans Organic Products. 5 years ago I added Potting Soil to areas that were problems because I used up my "Native Product that takes 1 year to develop. It worked wonderfully.