Early Stages: Immediately after planting, you will have to water more than you typically would water.
Summer: During the summer and the warmer months of the year, make sure to water the banana plant at least once every 2-3 days. Access to a sprinkler system may or may not provide sufficient amounts of water when it is hot outside.
Winter: Depending on how cold your climate gets, you may only have to water once every week or less. Your goal is to avoid making the plant sit in water so that it won’t rot.
Although it is better to plant in sunlight, if you plant in the shade you may have to water less. You can test the soil by sticking your finger in the ground near the plant. If the soil is moist for about an inch into the earth, you can wait to water the plant. If the soil is dry, you need to water the plant and continue checking on the soil every 2-3 days. Make sure to aim your water toward the roots and avoid watering the leaves.
Make sure NOT to overwater and leave the plant in a pool of water. Overwatering can kill the plant and or cause rotting of the root. An easy sign of over-watering or under-watering can be found in the leaves. Not enough water will cause the leaves to wilt and turn crispy while too much water will cause the leaves to wilt and be soft and limp.