The soil you bought should be fine, here's what I would do though. Buy a equal size portion of pro-mix, sunshine mix, canadian sphagum peat moss, (whatever you want to call it.) Then mix the 2 bags together for even consistency. Now get a big bag of regulaur perlite and mix that in there. You want a lot of perlite 20-40%, your plants are going to love you for it. Now since you have all that peatmoss add some dololimte lime, this is essential! Use 1 tablespoon per gallon of soil mixed in evenly for each pot.
I guarantee you this will be a good plant growing medium.