A banana tree is sensitive; it requires a specific environment to grow healthy and strong. Bananas are also healthy feeders, and require a lot nutrients to bear sweet fruit. To help the tree along, you will pay special attention to fertilization. How you fertilize a banana tree will vary based on the pH of the soil. Fertilization also varies as the season changes.
Find the pH level of the soil. Place a soil sample in the test kit tube and apply the included solution. Match the color of the soil and solution to the color chart provided to find out the pH level.
Create a watering schedule for the banana tree. The frequency of watering depends on the soil and, depending on the type of fertilizer you choose, the fertilization schedule may depend on the watering schedule. Expect to water the banana tree slowly and deeply every two to three days during the warmer months. During the winter months, cut back watering to once every two to four weeks. Stick your thumb 1/2 inch into the soil the morning after watering. If your thumb is dry, water the banana tree again. If your thumb is not dry, avoid watering until the soil is dry to a 1/2-inch depth.
Add a either balanced fertilizer or high-nitrogen fertilizer to the soil. Balanced fertilizer contains all of the micro and secondary nutrients required to grow a healthy plant. High-nitrogen contains a higher amount of nitrogen. Add the balanced fertilizer to the soil in small doses every time you water the banana tree. Add the high-nitrogen fertilizer to the soil once a month during the growing season in full doses. Read the fertilizer directions for the exact amount to apply to the plant.
Cut back on the high-nitrogen fertilizer, if you choose this option, when the plant flowers. Switch to a fertilizer that is high in potassium. If the soil has more alkalinity, or has a pH of 6.0 or under, stop fertilizing the plant when flowers appear. Continued fertilization can cause the fruit to turn black.