You are not alone: social media is full of claims that soaking banana skins in water makes a fertiliser that will give you bigger leaves and better blooms. The hack Put banana peels in a jar of water, leave them to sit, then pour the liquid on your plants. Bananas do contain potassium and small amounts of other nutrients. The snag is you have no idea how strong it is or what's missing.
The skins are rich in nutrients that are beneficial for plant growth and found in commercial fertilizers, including calcium, magnesium, potassium, and phosphorus. White vinegar makes soil more acidic, which can help certain plants absorb nutrients faster, and is also proven to extract minerals like calcium out of organic material, making it the perfect way to break down banana peels.