Not being The expert. I do know they need lots of potassium, If your soil is typical south florida sandy then I would use a fertilizer like 10-10-10- with micro elements. I do not know where you would purchase that in your area. But the micro elements will help any or most soil that is low in nutrients. I also cut any dying leaves in put them under the plants. I have large clumps. you could cut them in smaller pieces if they look too messy for you. I also cut the tops off after a hard freeze and let them return there energy back to roots of the clumps. After your banana is done fruiting that stalk will dye and you will need to cut it down and let the pups or younger plants grow to take its place.
James