For starters, the banana needs to be peeled and its bark washed thoroughly, because if you do not, the plants will receive some chemicals, but not the beneficial substances. The fact is that the banana peel has a coating of wax, like many other types of fruit, to make it more attractive to customers.
Another reason for wax coating is that the fruit is not damaged during transport. But it should be kept in mind that many manufacturers use plain wax and some are carcinogenic which is not safe.
Likewise, many suppliers use a solution of chlorine and ammonium sulfate to remove milk juice from a banana. It is understood that soaking the banana peel in such a solution does not add any beneficial properties to the peel. Some suppliers even use ethylene to make the fruits ripen faster, and this can be a pretty dangerous substance that has a negative effect on the human hormonal system.
If you can always choose organic banana fruits that will be a better and safer fertilizer for your plants.
