Go organic. Learn to mix a soil to have everything your plant needs and utilize beneficial bacteria. Best advice i can give for nutrition. Stear clear of bottled nutrients. Autos don't like loads of nutrients and dont like to be soggy wet. Coco i guess you can find a the pet store but id suggest getting a black trash bag and going into the woods. Find an old undisturbed spot where leaves have fallen and compacted for years. Lift the top layer away and harvest the fluffy decomposed layer, below that will likely be sand.
To mix a base soil you meed equal parts carbon rich fluff (decomposed leaves, peat moss, coco, biochar, whatever is available), sand, compost, and vermicastings.
Then you add a beneficial bacteria and a moderate dose of a dry organic fertilizer to turn that into a hotter soil. Lowes, home depot, and walmart have some ok ones.
My sig should help expand your concept of plant nitrition.