The Magical Power of Banana Peels in The Garden – Or Not

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Robert Pavlis

Banana peels are great for your plants, or at least that is what the internet says. You should bury some peels in the bottom of the hole when planting roses. You can add them to water and let them sit for a few days to make banana peel tea, an excellent fertilizer for indoor plants. Try drying them into a black leather and then crushing them to make banana skin powder which is great for the garden. I even found one web page that makes a fertilizer spray out of them.

Eating banana peels is also a hot topic and they reportedly provide all kinds of health benefits and even whiten teeth.

Lets have a look at the reality of banana peels for plants. Are they better than just another source of organic matter?

The Magical Powers of Banana Peels in The Garden
The Magical Powers of Banana Peels in The Garden

Banana Peels for Plants – The Claims

I started this post when I saw a YouTube video that claimed banana peels have an NPK of 0-25-42.

When you see claims like this it is critical that you give them a quick sniff test for reality. Does it make sense? Does it seem realistic? If not – run for the hills because the rest of the advice is now suspect.

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A banana peel is part of a plant. A plant needs protein to function – all living organisms have this requirement, and protein contains nitrogen. Clearly the number zero for nitrogen is complete nonsense. No living organism, including all plant material has a nitrogen level of zero.

All living organisms contain water, and in fact they contain a lot of water. You probably know humans are mostly water and so are plants. This number is around 80%. If a banana is 80% water, how can the potassium level be 42%?

Even if you didn’t know the 80% moisture value, the above NPK number says that 67%, or 1/3 of a banana peel is phosphate and potash. Does that make any sense at all? NO!

This is not the only site that claimed a 42% potassium level, which is completely ridiculous.

YouTube video

The Question to Ask

All organic matter is good for soil and plants. They all provide a carbon source and plant nutrients as the organic matter decomposes.

The important question is, are banana peels significantly more nutritious than other sources of organic matter. Do they provide any unique beneficial chemicals? If they do, they might be a superfood for plants.

Vague Claims for Banana Peels

Do a bit of Googling and you quickly find all kinds of claims saying banana peels have a “high” nutritional value. Some even say the peel has higher nutrients than the banana.  This sounds convincing, but you may have noticed that there are no numbers included in these statements.

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What does “high’ mean? And how much higher is it compared to other organic matter? Without numbers, these are just fancy words to try and convince you to believe a story.

Dry or Wet Weight?

Even when numbers are supplied, there is still a big problem with the data. Is this based on wet weight or dry weight? When someone says a banana peel is 42% potassium, is that based on a normal wet peel or a dry peel? This is a crucial point since most of a banana peel is water.

Chemists get around this problem by reporting chemical content on a dry weight basis. But many sources take these numbers, if they even bother to look it up, and present them as a wet weight, which exaggerates the value by a huge amount.

Chemical Analysis of Banana Peels

Several nutritional experts made the claim that banana peels have not been studied for nutrients, but I had no problem finding some studies.

Note: Except for the moisture values, all percent values are based on dry weights.

Sources: Source A, Source B, Source C, Source D

The average nitrogen in protein is 16%, so the 3.5% protein in banana skins is equivalent to 0.6% nitrogen.

The above table reports values for potassium and phosphorus, but NPK uses values as potash and phosphate. The potash and phosphate in banana peels is 11.5% and 0.4%.

The NPK value for banana skins is 0.6-0.4-11.5. But this is the value for dried banana skins since all of the above values are calculated on a dry weight basis. The NPK of fresh banana peels is 1/5 of that, making an NPK of 0.1-0.1-2.3.

For comparison, purchased bagged manure is around 1-1-1.

Are Bananas High in Potassium?

Not really. Bananas have more potassium than some other food, like grains and meat, but all fruits and vegetables are higher in potassium – “there is nothing special about bananas. Tomatoes, potatoes, and beets also have potassium and often more potassium than your average banana.”

One cup of chocolate milk contains the same amount of potassium as a banana.

Magical Properties of Banana Peels

There are also some vague claims of other important chemicals in banana peels that might be beneficial to plants, but I found no specific claims that could be reviewed.

There are many more claims for our health, including things like antioxidants, but a cursory look shows that the science is not there for the benefit of these, at least not yet.

Banana peels are just another source of plant organic matter.

Banana peel tea is NOT a good fertilizer, photo source:
Banana peel tea is NOT a good fertilizer, photo source: Pinterest

Banana Peel Tea

Some claim you can steep banana peels in water, either using hot water, or just letting them sit for several days in the sun.

I have reviewed the value of using left over tea before and this tea would be no different. There is limited decomposition during the process of making it, which means that most of the nutrients remain in the peels.

Potassium leaches out of organic matter more quickly since it is not chemically bound, and banana peels have a higher level of potassium, so the tea might add some potassium, but not much else.

Don’t get conned by tea claims for plants.

YouTube video

Banana Peels for Roses

This is a very common piece of advice. Place some banana peels in the hole before you plant roses. Some even take the time to cut them into small pieces.

Why just roses? If this was good advice, would it not be good advice for all plants? Or is just that roses love bananas – or is that garlic?

As banana peels compost, they turn into black mush. I just can’t see this being good for new tender roots?

Look at the NPK. It is very high in potassium relative to nitrogen and phosphate. That is not an ideal ratio for plants. To compensate for this some people add eggshells! We know eggshells don’t decompose in most soil, and how would adding calcium balance the problem?

This idea probably started because people believe bananas have a high potassium level, and we have the very common myth, that potassium stimulates roots – which it doesn’t. From this misinformation it naturally follows that banana peels stimulate roots and flowers on roses?

This is just a dumb idea.

Bury Them Around Plants

If you forget to add them to the planting hole you can dig up the soil around the roses, add the peels, and cover them with soil. Roots grow in the top few inches of soil – digging around the base of shrubs is never a good idea.

What Should You Do With Banana Peels?

Banana peels may contain a psychoactive substance, and smoking them may produce a “high”, or a sense of relaxation. This may be a myth associated with the 1966 song “Mellow Yellow” by Donovan.

Apparently, some people even eat them as a cooked desert or a smoothie drink, and that is OK. A vegan food blogger’s recipe uses banana peel as a ‘pulled pork substitute’ – I don’t think so!

Banana peels are just another form of plant-based organic matter. Add them to the compost pile, or spread them on the ground to decompose. They will add value to both the soil and plants but they are not a superfood.

Don’t get hooked in by all the crazy ideas on the internet.

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

92 thoughts on “The Magical Power of Banana Peels in The Garden – Or Not”

  1. The only way I see banana tea even having a chance of really working is giving it lots of time to break down completely or at least almost completely. It’s silly to think that a couple of days in water and it becomes some miracle tea. If that was the case then we would be growing bananas and making banana teas for field crops. 5 minutes of just thinking about it and tells you that it’s BS.

    Reply
    • You probably know humans are mostly water and so are plants. This number is around 80%. If a banana is 80% water, how can the potassium level be 42%?
      😂😂😂 yes 80% for a newborn baby, you on the other hand will have about 55-60%

      Reply
  2. Doesn’t matter what anyone has to say, we’re automatically wrong🙄 Even though this has worked for many…yes, even with one pot receiving it, and the one next to it NOT receiving it. I’m sure he’d say it was just the individual genes of the plants themselves 🙄 He obviously has some miracle fertilizer of his own that he’s probably selling 😂

    Reply
      • Linda has apparently performed a statistical trial with sample size = 1, plus 1 control. Next step – do a field trial with a large sample size and large number of controls.

        Reply
  3. Use of banana peels within 6-10 inches of the surface has been highly effective in my gardens where I used earthworms and net neutral in the gardens without them. My unscientific theory is that decomposing banana peels attract worms to a specific location bringing nutrients and burrowing areas for easier root growth. The results are good enough for me in the Southern US to keep doing it in my beds that have earthworms.

    Reply
    • 1) You presented no data to show it was “highly effective”.
      2) Yes – decomposing organic matter will attract worms – the post is not about that. But banana peels are no better than other organic matter.

      Reply
      • Robert, there are some practices that work wonders on plants that have no scientific explanation, yet. Gardeners have been using certain pest control practices ( ex. marigolds) for years. It works. The certified lab only provides the percentages (NPK). The lab does not tell you how the plant absorbs it. Like humans, plants have preferences.

        Reply
        • 1) Gardeners only think these practices work. For example, marigolds don’t work for keeping pests away – they actually increase the number of pest.

          2) “The lab does not tell you how the plant absorbs it.” – actually research has provided a huge amount of material that describes this.

          3) ” Like humans, plants have preferences” – no. Humans have preferences based on taste and pleasure. Plants do neither of these. All plants need about the same amount of nutrients and use them for the same reason. The differences between plants is minor. I don’t eat brussels sprouts, but you will never find a plant that does not absorb nitrogen.

          Reply
          • Of course why certain practices “work wonders” in the garden mythosphere, while they don’t give significant differences in controlled trials, is also a subject worthy of study.

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