It’s hard to miss the media hype about banana peels and their practically miraculous properties in the garden. They’re full of potassium, is the main claim, and plants need potassium. Just add them to the soil and your plants will grow like never before, many garden miracle sites insist! Facebook users share this kind of information as if they’d just discovered the Holy Grail. And yet, there is really nothing miraculous about banana peels.
The common garden myth is that you should “feed” banana peels to your garden plants or even houseplants, either whole or chopped up or turned into banana tea. However, try it and you’ll see. In most cases, if you remove the wishful thinking factor, plants so treated will do no better than other garden plants that didn’t get the treatment.
Yes, banana peels do contain minerals, especially potassium and magnesium, and can be used, once decomposed, to fertilize plants. That sounds promising! However, most garden soils aren’t seriously lacking in potassium and magnesium. Plants will only absorb minerals if they need them, so adding more to a well-stocked soil won’t improve your results.
OK, though, let’s assume your soil really does lack potassium and magnesium (we’ll assume you’ve done a thorough soil analysis to find that out). Why then add banana peels? Many other plant residus contain more potassium and magnesium than they do (scraps from avocados, potatoes, melons and squash, notably). And you probably already have fertilizers you could apply that have a decent share of the two elements. Plus, unlike most other plant residues, banana peels contain no nitrogen worth mentioning, and that is the one mineral that really is lacking in most soils. If you “fed” your plants nothing but banana peels, they’d likely be in serious trouble.
Dropping banana peels at the base of plants is pretty innocuous, neither terribly useful nor terribly harmful, although they’ll decompose much more rapidly if you chop them up first. Banana tea? Why dilute a product that isn’t all fabulous to start with? Might as well use the peel whole! And as to adding peels to houseplants … well, fairly little decomposition goes on in pots indoors, so any benefits will be very long term. And besides, aren’t you concerned about fruit flies?
Finally, actually dropping banana peels into the bottom of a planting hole to nourish the plant—a common recommendation—is probably going to be more harmful to the plant than good for it. As the peel decomposes, that will leave an air pocket (not a good thing), then the soil will likely subside, causing the plant to sink, also not good for the plant.
Actually, banana peels are just an organic plant waste product like so many others, best used in the compost bin, where a mixture of products, each with their strong points and their weak ones, combine to make a really great garden product: compost.
Use, do compost your banana peels (along with other table scraps) and use the compost in your garden, just don’t expect miracles!