The common advice to “boost” your soil potassium levels with banana peels to improve plants is misleading and contradicts what we know about soil, plants, and their nutritional needs.
This is part of a series where we look at popular garden advice and check if it is fact or myth.
Banana Peels in the Garden
If you do a quick Google search asking about bananas as fertilizer for the garden, a whole bunch of banana remedies and questions come up:
- banana peel fertilizer spray
- banana peel fertilizer for tomatoes
- banana peel and eggshell fertilizer
- how to make banana peel tea for plants
- are banana peels good for all plants
- dried banana peel powder
- how to make banana peel liquid fertilizer
- banana peels egg shells coffee
The gardening world is bananas for banana peels! But, WAIT.
Is this stuff true? Are banana peels really a plant superfood? Can they fertilize a garden? Will they give my plants a special boost?
Time to check the facts.
If you just want the short answer, no, they are not anything special and take a long time to break down.
Contents
Are Banana Peels Good for the Garden?
Most claims about using banana peels in the garden imply they provide some sort of incredible plant fertilizer.
And I think I see where this idea came from.
There are a lot of banana eaters in Canada and the United States. And that’s a lot of peels to dispose of.
The message is hammered into us that bananas are a good source of potassium.
And, it’s well-known to gardeners that potassium is one of the three macronutrients in fertilizers—the K of N-P-K (nitrogen-phosphorus-potassium). You can read the basics on fertilizers here.
So, putting the peels in our gardens seems like a great way to reduce food waste and help the garden. Right?
Yes, but. Not so fast.
Banana peels are a good source of nutrients—as most kitchen scraps are—and that’s why all these things are a welcome addition to our compost piles.
Each decomposes in its own time, and together a variety of scraps, provide an array of essential nutrients.
But, there are no superstars in the compost pile: it takes a variety of once-living things to make good compost. And individual plants and the soil conditions will determine what’s needed.
And it’s going to take a banana peel a very long time to breakdown and give what it has to offer.
So the short answer is: no, there is nothing special about banana peels, and, keep reading to find out why they could cause problems.
Related: Is Dish Soap a Natural Pesticide?
The Problem With Banana Peels
Contrary to the hype, there’s nothing unique or even rare about banana peels that requires they be treated differently from other kitchen scraps.
Even as a source of potassium, there are actually lots of fruits and vegetables that have as much or more potassium than bananas (per gram). Avocados are one example.
Bananas Are Not Magical Fertilizers
Soaking banana peels in water to produce ‘banana tea’ (like compost tea) isn’t going to do anything special for your garden.
And there’s nothing to support the idea that tossing banana peels in your planting holes gives plants a boost.
In fact, it could be problematic.
First, the bulk of the peel is going to create an air pocket around the plant roots —something you do not want.
Banana Peels Are Slow to Decompose
From there, banana peels are very slow to decompose, so even if there was some benefit from the nutrients, they are not going to be available any time soon.
And finally, just because potassium is one of the macronutrients for plants, does not mean more is more!
Plants Cannot Overeat
Plants can’t take up nutrients just because they are available: they take up nutrients when there is a need and they are able to.
This is why a soil test from an accredited lab can be so helpful: it will tell you what your garden soil actually needs.
And that’s why it’s smart to feed a known need, not just toss stuff at the garden and hope it helps.
Bottom line, yes, always put your fruit and vegetable scraps in the compost bin: it is much better for the environment than sending them to landfill.
But, despite the hype, banana peels are nothing special, and will not give your tomatoes or anything else a special boost.
Related: Soil Testing: Home Test Kit versus Lab
Resources
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Garden Myths
We have more articles on garden myths, misinformation, and folklore here. Topics include Epsom salt, eggshells, and more.
Garden Soil 101
Soil | The foundation of your garden. Know what you’ve got and provide only what it needs.
• Mulch | Add 2-inches of organic matter to protect soil, retain moisture, and gradually fertilize your soil.
• Leaves | Finely chopped fall leaves make excellent mulch.
• Leaf Mold | Decomposed fall leaves beneficial to soil structure.
• Compost: Decomposed organic matter providing nutrients for the garden.
• Potting Mix | Contains no soil: designed to optimize plant growth in pots.
• Seed Starting Mix | A lightweight potting mix for sowing seeds in containers.
• Soil pH | Knowing your level (which may vary) is informational, not a call to action. Most soils fall in the range of 5 to 8 and accommodate a wide range of plants.
~Melissa the Empress of Dirt ♛