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Please Don’t Make Banana Peel Compost Tea Fertilizer For Houseplants

Always on the hunt to reduce food waste, I saw a bunch of people share about banana peel compost tea (or liquid fertilizer) on social media. According to Pinterest, it’s a trending topic. Intrigued by this little food waste reduction experiment, I tried it, and I will never do it again! Read on for more about my disappointing experience with this trendy soil amendment and why I think there are so many better alternatives.

A few months ago, we bought this Vitamix blender and have been eating lots of smoothies for breakfast. This mango and banana green smoothie is my favorite, and I make some version of it nearly every morning. As a result, we have an excessive number of banana peels piling up in our compost bucket.

I know they will go to good use in my compost pile, but I have a growing collection of indoor houseplants that I wanted to feed too. Enter banana peel compost tea fertilizer (a liquid soil amendment). If banana peels make a compost bin happy, surely they would make soil happy, right?

Nope! Stop right there. Please skip the banana peel compost tea fertilizer. Let me explain.

Banana Peel Compost Tea Experiment Planning

A couple of months ago, with plenty of banana peels at my disposal, I decided to try making banana peel tea fertilizer for some of the plants in my house. It was popular on social media, after all, so why not try it? (Note to self: social media popularity alone is not a good reason to try something new…)

I’m a houseplant newbie. I dove headfirst into houseplant territory just about a year ago with my Succulent Studios subscription and have been steadily adding to my indoor garden. But I’m far from an expert on the deep science of soil, so a bit of due diligence was in order. 

I did a little research to ensure I would not burn the roots of my plants or cause other damage with my banana peel fertilizer experiment. Admittedly, I didn’t dig that deep into the archives of the internet, but I didn’t see any immediate red flags. Planning complete.

What did I have to lose besides a couple of small succulents that became my experimental ground?

How To Make Banana Compost Tea Fertilizer

After cutting up a few brown bananas to put in the freezer for smoothies, I chopped up the peels and shoved them into repurposed glass jars. I have (probably) too many repurposed glass jars, so I made a few batches of this supposedly miraculous liquid fertilizer and perfected my patience.

The banana peel compost tea fertilizer is a cinch to make (which is probably why it’s so popular on social media). The bright yellow peels pop on a pretty Instagram feed too! It all just makes social media sense. I’ve included the simple recipe at the bottom of the post, but it goes like this:

Ingredients + Materials

  • 3-4 banana peels
  • Quart-sized jar  – we use repurposed pasta jars
  • Water – to fill the jar

Step-by-Step Instructions

  • Add chopped banana peels to the jar.
  • Fill the jar to the top with water, enough to cover the banana peels.
  • Close the jar and allow it to rest for a few days or a week.
  • Remove the peels and water plants with the banana peel tea fertilizer.
  • Watch magic happen!

Because I got carried away with life, I let it sit for a couple of weeks in the jar. Then I watered a few of my houseplants (mostly succulents) with the fancy water.

Banana Peel Compost Tea Epic Fail

Things started to get murky pretty quickly.

As soon as I opened the jars, I didn’t have a warm and fuzzy feeling about the banana peel tea fertilizer. It smelled suspiciously sweet (like it would attract bugs), and the whole process was kind of messy.

Immediately, I noticed stains on several of the leaves of my succulents. While the stains appear to be permanent, they don’t seem to have caused harm. But who wants to stain their beautiful succulents when they water them?

Also, the soil continued to smell like a combination of sweet and somewhat rotting banana peels for many days after watering it. This made me nervous about the lasting effects.

Within just a few days, the real problem began. I started noticing little gnats flying around the soil. I’ve had succulents and several other plants in my home for over a year. I’ve had no persistent issues with bugs in my home… until this banana compost tea situation.

Hindsight is 20/20, but I soon realized that I forgot to research other potential side effects. I started to dig a little deeper into the science behind why banana compost tea might work or not work and found some opinions about its lack of efficacy that were quite compelling.

I threw out the remaining banana peel compost tea and continued watering the plants at regular intervals with tap water. Over the course of a couple of months, however, the fungus gnat problem grew, and they began spreading through the rest of our house.

Little gnats flew into our faces while on Zoom conference calls. They buzzed in our ears as we fell asleep at night. They even showed up in our bathroom, and are flying in my face as I write this post. It’s gross! And now I don’t know how to get rid of them.

After some further research, I’ve come to believe that the sweet remnants of rotting bananas with which I watered the soil attracted the fungus gnats and became food for their families. They continue to lay eggs in the soil, and I’ve got quite the project ahead of me to stop the reproduction cycle to get these guys out of my house!

Why Would Banana Compost Tea Fertilizer Even Work?

In retrospect, I started to apply my knowledge of composting to this experiment. I’m not a scientist or compost expert (at all), so I’m not purporting to have all the definitive answers on banana peel compost tea. I’ve never done any replicable or peer-reviewed research on which to base formal conclusions about the efficacy of banana peel compost tea.

But the more I think about how it might work and why it might work, the more I think it’s relatively useless. I think banana peel compost is only popular because it looks pretty on Pinterest and Instagram.

P.S. Banana peel compost tea is trending on Pinterest this year, so banana-fanatics beware.

How Does Banana Peel Tea Fertilizer Help Plants Thrive If It Even Works?

The lore goes that bananas are good for plants because they provide a lot of potassium, and potassium is an essential element for plant growth. Potassium helps plants grow strong roots, use water effectively, and resist drought. It also enhances fruits and vegetables, so it can be particularly helpful for growing edible gardens and food crops. 

If soluble potassium (or potassium that plants can access through water) is deficient in soil, plants may experience stunted growth or other symptomatic issues that cause plants to be weak and more vulnerable to unfavorable conditions.

Did you know that potassium is a mobile nutrient, meaning a plant can reallocate potassium throughout itself? As a result, older (lower) leaves on a plant tend to show signs of potassium deficiency before the younger (higher) leaves because the plant sends what little potassium it has to the younger, developing leaves. Isn’t this a neat function of how plants look out for themselves and their future health? I digress…

To the extent potassium from the peels decomposes in the jar and becomes water-soluble, it only makes sense that plants that love potassium would love banana peel soil amendments. Right? Even humans eat bananas for their potassium. All plants need some level of potassium, and it helps plants more effectively absorb other nutrients in the soil as well.

But there a few key points where the logic breaks down (unlike the banana peels in my airtight jar of water).

  • Plants don’t eat bananas; plants absorb nutrients from the soil.
  • Plants need more nutrients than just potassium; they want a balanced diet.
  • Bananas aren’t the best source of potassium, so why do they reign supreme on the potassium pedestal?

Let’s address each one individually.

Plants Don’t Eat Bananas

Unlike humans, plants don’t eat bananas. Plants absorb nutrients from the soil and can only do so after complex nutrients are broken down by microbes and fungi into a form that is available to plants.

In order for plants to benefit from a potassium boost from banana peel tea fertilizer, the peel needs to breakdown such that the potassium becomes soluble in the water. If not, the potassium will remain in the banana peel that you end up removing from the jar and tossing into the compost pile.

In ideal conditions in a compost bin flush with oxygen, water, nitrogen, and carbon, we can speed up nature’s natural decomposition process. But the process to break down organic matter still takes at least a couple of weeks, and this is a best-case scenario.

We know from composting at home, that finished compost (that is ready to feed plants) takes months to decompose without sufficient air and active management. Why then would banana peels break down with abandon in an enclosed glass jar of water on my counter at room temperature in a few days into something suitable for plant absorption?

In other words, my rational (though admittedly not professorial-level) science brain doesn’t believe any sort of suitable decomposition happens in two days to a week… or even two weeks if we’re being generous. Thus, that smelly solution I served my plants was most likely just brown-tinted water with a spattering of rotting banana peel pieces attracting fungus gnats.

Fantastic! (Please tell me you can hear my sarcasm through the screen…)

Plants Prefer a Diverse Diet of Nutrients and Minerals

Plants need lots of different nutrients and minerals to survive and thrive. Variety is the spice of life. Nitrogen, phosphorus, and potassium are three of the main nutrients that are vital to their health and growth. However, different types of plants prefer varying levels of these (and other) nutrients in the soil.

Just for fun, let’s suppose our precarious banana peels could break down in two days to a week and create a liquid fertilizer lush with water-soluble potassium our plants will eat right up. Is banana peel compost tea fertilizer a complete nutrient solution?

Probably not. Bananas and banana peels are high in potassium, but they aren’t particularly loaded in nitrogen and all the other nutrients that plants need to grow. If the peels aren’t high in a variety of nutrients, they won’t provide those nutrients to plants. So your plants will probably need some additional, more complete fertilizer every once in a while.

Alternative conclusion… banana fertilizer compost tea is pointless (except when it causes fungus gnat infestations in your home, and then it’s straight up annoying)!

Better Sources of Potassium Than Bananas

Aside from the fact that I’m not even sure banana peel compost tea actually works, bananas aren’t necessarily the best source of potassium. For example, a medium-sized baked potato has twice the amount of potassium as a medium-sized banana. A half-cup of pinto beans has about as much potassium as a banana. And papaya and prune juice can go toe-to-toe with a banana when competing over potassium levels.

Heck, why not butter up my succulent soil with baked potatoes and quench my plants’ thirst with prune juice?! Because it’s gross, and it attracts pesky bugs, just like banana peel compost tea. There’s more to life than a pile of potassium…

If Banana Peel Tea Fertilizer Doesn’t Work, What Other Organic Fertilizers Can I Use?

Compost. Compost. Compost.

I might be a tad bit biased. I’m a self-proclaimed compost nerd, after all. There are many ways to fertilize plants, including a variety of organic and natural options, but composting is queen. Compost is one of nature’s most effective methods for regenerating soil and recycling nutrients for renewed life.

We compost (in all the ways), so we use finished compost as a soil amendment in our garden and on our houseplants. Because finished compost is created from a variety of organic matter, it will naturally compromise a greater variety of nutrients for growing plants than a lone banana. If you have finished compost, that’s always a great way to feed your soil and help your plants flourish.

So What About The Banana Peel Tea Fertilizer?

Banana peel tea fertilizer is potentially a fun way to feed your outdoor plants. But honestly, I’m not sure I ever want to take the risk of introducing this in my home again. I’d much rather just compost all these banana peels. There are so many ways to compost at home. Even if you have a garden and no compost system, bury the banana peels in the soil outdoors before attracting pesky insects into your home with rotting fruit.

We’re still making lots of smoothies for breakfast, so I have a pile of banana peels each week that are way too good to waste. Ours will all end up in one of our compost bins. If you’ve successfully used banana peel fertilizer, I’d love to hear about your experience. I’m curious to know two things: 1) How did you make it without attracting annoying insects into your home? and 2) How do you know it actually worked?

Drop some knowledge on me while these fungus gnats are driving me bananas!

Banana Peel Compost Tea Fertilizer

Banana Peel Compost Tea Fertilizer

Prep Time: 5 minutes
Active Time: 5 minutes
Additional Time: 5 days
Total Time: 5 days 10 minutes

Simple banana peel compost tea fertilizer that sounds fun but may not be what you expect. Banana peel lover beware.

Materials

  • 3-4 banana peels
  • Water - to fill the jar

Tools

  • Quart-sized jar  - we use repurposed pasta jars

Instructions

  1. Add banana peels to the jar.
  2. Fill the jar to the top with water, enough to cover the banana peels.
  3. Close the jar and allow it to rest for a few days or a week.
  4. Remove the peels and water plants with the banana peel tea fertilizer.
  5. Watch magic happen!
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Deb

Wednesday 14th of April 2021

Hi, you can use matchsticks to get rid of fungus gnats - here’s an article that explains how:

https://www.askaprepper.com/why-you-should-place-matches-in-your-plant-pots/

Jen

Wednesday 14th of April 2021

Thanks for that idea!

Darcy

Tuesday 6th of April 2021

Steinernema feltiae nematodes are the best cure I've found for fungus gnats. (I've gotten them frequently, unfortunately, since they tend to infest store-bought potting soil.)

Jen

Tuesday 6th of April 2021

Thank you for this tip!

Dee

Friday 2nd of April 2021

Did you filter it after? I always filter out pieces of food at least twice, and I also always use an environmental protection management product

Jen

Friday 2nd of April 2021

I didn't. I probably should have (ha). Do you have any recommendations for products you use to filter it? Also, what is an environmental protection management product? Thanks for your advice!

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