Yeah if you want to add your own blend of nutes premade soil isn't your best option, these soils are practically supersoils especially fox farms, the manufacturers won't tell you this cause most sell nutes too but there are people that grow autos in fox farm soil with no nutes at all the entire grow and do fine same with my soil and honestly my first plants did better with min nutes. For you coco would be better anyway like you said hard to get soil in your area.