The size of the fruit varies depending upon the variety of banana, so isn’t always a good indicator for picking bananas. Generally, banana tree harvesting can commence when the fruit on the upper hands are changing from dark green to a light greenish yellow and the fruit is plump. Banana stalks take 75-80 days from flower production to mature fruit.
Before picking bananas, look for “hands” of fruit that are filled out with no prominent angles, are light green and with flower remnants that are easily rubbed off. The fruit will generally be 75% mature, but bananas can be cut and used at different stages of ripeness and even green ones can be cut and cooked much like plantains. Home growers will generally harvest the fruit 7-14 days prior to ripening on the plant.
Once you have ascertained that it’s time for banana tree harvesting, use a sharp knife and cut the “hands” off. You can leave 6-9 inches of stalk on the hand, if you wish, to make it easier to carry, especially if it is a large bunch. You may end up with one or many hands when harvesting banana trees. The hands don’t usually mature all at once, which will extend the time you have to consume them. Once you are done harvesting the banana trees, store them in a cool, shady area, not the refrigerator, which will damage them.