Some of the best fertilizers include Worm Castings (little N, Mg, other micros), Fish Emulsion/Hydrolyzed Fish (5-1-1, some of every nutrient), Maxicrop Soluble Seaweed Powder (1-0-4, micros), Bone Meal (P, a little N, lots of Ca, Fe, Mg, etc.), Blood Meal (12-0-0, lots of Fe, other micros), Bat & Seabird Guanos (N &/or P, high in most micros), and Palm Bunch Ash (0-0-30, best organic source of K).
The ash works so well for flowering, we just gave it to some K-deficient, 24/0 vegging plants and it caused them all to develop preflowers without a dark period. Not autos, either.