I use PRO-Mix. It comes in several formulations. I use BX cause that’s the only one my supplier carries. I add extra Perlite (I don’t measure) and crab shell (approx 2% volume of soil), kelp meal (approx 1/2 to 1 tablespoon per gallon of soil) and a general-purpose granulated vegetable fertilizer (this year is was Jobe Tomato and vegetable 2-5-3, approx 2 tablespoon to 5 gallon of soil)
I fert my potted trees every 14 days rotating between Miracle Grow (24-8-16), fish fertilizer (5-1-1) and fish with seaweed fertilizer (2-3-1). All my in grounds died to the ground so they are also getting ferts.