Basic Bonsai Nutrition
Old school bonsai masters will tell you that organic is better than chemical when it comes o fertilizers because chemical fertilizers will often result in poor soil condition. It is also very dangerous if not applied correctly. They perfer cottonseed meal, blood-meal, bone meal, fish-meal or other animal manure.
Old school masters also mix there own "cakes" using a mix of those ingredients with a little water.
When I finish this article you will be able to decide for yourself which is best and what product works best for you. Until then . . .