missoss , What I found when I first started was to study the N.P.K and what each one doe's for the plant , and never fell stupid mate , there is a lot to learn if you go down the path of ratios , I used to use Advanced Nutrients when I first started but way to expensive , when I went organic I first copied there NPK . Also General Hydroponics Cal/Mag is 1.0.0. so you will need that on hand to . I use it for when I don't want a high nitrogen input . So with the 5 basic items you can get local without the big cost you can have a good grow , I use other stuff , but first learn the basic , but I 'll tell you about it another time . You can also pm me with any questions you like .