Go to bananas.org . Very knowledgeable people on that site and they probably have a thread on that subject. I take it u are in south Florida. I have several in ground. I will throw a pound or so of Palm fertilzer or regular 13-13-13 around mine when they are growing and water with Miracle - Gro every week or so. They say it's hard to over do fertilizing and watering when they putting out growth.I will buy palm fertilzer for mine when i can find it.They it's better.

Milorganite is a nice natural fertilizer the bananas seem to do well with. It will never burn. You can dump 1/2 bag around big ones.