do you know what is the reason for the effect of banana skin on stimulating hormones or is it just a trend?
Banana produces a bunch of ethylene gas, which is known to evoke a stress response in plants. In a closed environment..
Banana itself contains a lot of potassium which in theory is good for fruits and roots, in practice it doesn't make much of a difference.
Banana also contains a bunch of starch and sugars, which help inhibit root growth and photosynthesis: if a plant can get sugars from the soil it will produce less efficient roots and way less powerful foliage.
It's a trend, as are most tiktok/insta plant health tips: somebody took a scientific article, remembered it 10 years later and called it a fact, then 1000's of people took that fact and promoted it as something they found anew.
I have a love/hate relationship with that kind of crap. On one hand I love people killing their plants by doing stupid trends without spending three minutes to dive into some google search, on the other hand I hate that they come to gardening forums for help instead of calling the original poster out.
One perfect example is the bicarbonate bullshit year. That was 2018 or 2019. People got a lot of mildew and Potassium bicarbonate can (to some extent) treat it. Hydrogen peroxide is better at it.
Potassium bicarbonate is sold as baking soda.
The cheapest baking soda however.. Is sodium bicarbonate.
Sodium is a metal that only halophylic plants can survive. Plants that live near the sea.
So when whole communities of plant lovers started killing their plants with sodium poisoning, a bunch of gardening forums were flooded with orange looking plants. Well, the mildew was gone!
So were the plants.
Heck, we have that in the bonsai community too! A couple dudes were heavily promoting compost tea and one dude nearly killed half of his stock with it because he didn't know what he was doing. Another dude was telling the world he cured apple cedar rust with ProBio Carbon and a year later he no longer dares to specifically claim
any beneficial effects for some reason. I wrote an extensive review for the stuff and it doesn't cure anything except root rot in houseplants.
Good that you ask around first. One thing about banana peel water is that it's going to ferment in your soil, causing heaps of carbon dioxide buildup and acidification if there's too little air flow. Eventually that's a plant killer.