Going Bananas, Part I
By Glenn Teves, County Extension Agent, UH College of Tropical Agriculture and Human Resources
Banana is the most important commercial fruit in the world and is native to the tropics. It’s a good source of dietary fiber, vitamin C, potassium and manganese, and a very good source of vitamin B6. Banana has been described as a perfect snack for athletes to restore an important electrolyte, potassium, to the body. It’s also vital for kupuna who have a higher demand for potassium than the rest of us.
Banana is adapted to the wetter lowland areas of the island, but with adequate water, can grow anywhere. There are a handful of major pests, including the banana weevil bores into the corm and can lead to early decline. Flower thrips feed on the fruit surface causing unsightly silvering and bronzing. Black leaf streak fungus, also known as Sigatoka disease, is a winter problem in rainy areas, but is something we live with since it’s costly to spray throughout the rainy season. Leaves will have black streaks that increase to the point where the whole leaf dries up. Drier lowland areas have less of this problem, and good air circulation and wide spacing can mitigate the problem.
Propagating new plants are accomplished by digging out sword suckers or keiki with large bases, ideally about two to four feet tall. Clean planting material by first cutting off both the top half of the plant and the bottom half of the corm. Inspect the corm and shave off the outside skin until the corm is white, and also one leaf wrapper. Black holes usually indicate the presence of disease or banana weevil. Clean planting material will also prevent the introduction of pests into your new planting. Plants are then soaked in a dilute mixture of one part Clorox to 10 parts water for five minutes to surface sterilize the propagating material.
Banana is fairly easy to grow, and is best started in a two-feet deep hole where it’s easy to flood the plants to water. At planting, leave the top of the plant uncovered, and the dirt will fill in by itself. Allow plants to dry up between watering since roots will be slow to emerge, and too much water will rot them. As plants start to grow and send up new growth, water can be increased. Once established, banana requires a lot of water for a good yield. A healthy field of banana can live for 20 years or more if well cared for. Each mother plant with its keiki around it is called a mat, and plants will spread out in all directions.
Banana is heavy feeder of nitrogen and potassium, so special formulations of fertilizer are made for this crop, such as 10-5-25, 8-3-33, and others. A soil sample will help you determine if other amendments are required, such as lime or dolomite to adjust the acidity of the soil. Next time, we’ll talk about the different varieties of banana.