Banana trees are not just for commercial growing anymore. There are many varieties of smaller or dwarf banana plants that can be grown indoors or outdoors all year long, depending on the climate. But the one thing all banana tress have in common is their need for a quality fertilizer, which will not only help the tree remain healthy and strong, but will also give the biggest yields of delectable fruit.
A standard water soluble fertilizer is labeled as NPK type. The initials stand for the basic building blocks of all fertilizers: nitrogen (N), phosphorous (P) and potassium (K). Every plant has its own fertilizer requirements; some may like more nitrogen than others while some may like more potassium. Regardless of the plant type, all fertilizers will ideally contain all three of these ingredients.
Balanced Fertilizer for Bananas
Bananas do best when they are given a balanced fertilizer, meaning all of the NPK values are roughly the same. Recommended for the best growth is an 8-10-8 NPK fertilizer compound, and although other types can be used, the growing results will be mixed and fruit setting may be compromised.
Banana trees are very heavy feeders and need to be fertilized a lot to maintain vigorous growth. There are several ways to do this: A small amount of fertilizer can be applied every time the tree is watered, or a larger amount can be dug in around the plant and allowed to dissolve each time the plant is watered. Mature outdoor plants consume 1 1/2 pounds of 8-10-8 fertilizer per month; dwarf indoor plants require only half that amount.
Light applications during watering is the ideal way to fertilize banana trees. Mix the fertilizer with the water and apply as you would normally water the plant. Test the soil with your finger often, and when the soil dries out down to only 1/2 inch, water and lightly fertilize again.
An alternative is to spread the fertilizer out and away from the trunk of the tree; for mature plants outdoors, this will be approximately 4 feet. Dig it in slightly and then water as normal, checking the soil with your finger to maintain adequate moisture levels.
Bananas are a tropical plant, meaning they need constant heat as well as moisture and fertilizer to grow lush and set fruit. Rich, well-drained soils will allow banana trees to do their best, and temperatures should range from the 80s during the day to the high 60s during the night. Outdoor plants can be covered during the coldest nights, but unless you are willing to dig them up every year and bring them inside, banana trees should not be planted outdoors in northern climes.