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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 (at least the simplified version that’s popular on social media). 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 trendy 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.

Update: Since initially posting this, I’ve received several (mostly well-intentioned) emails suggesting the recipe is incomplete. Specifically, readers have recommended using aeration tools and/or straining the compost tea to prevent any fruit chunks from ending up in the soil. If you choose to make banana peel compost tea, I assume these additional steps would create a better final product. That being said, I’m still not sold this is the best way to fertilize plants (which I explain in more detail below).

Furthermore, I used the recipe above to test the common, simplified version I’ve been seeing on social media. I included the recipe so you can see what didn’t work, and then decide for yourself if another banana peel compost tea recipe might be better. In my opinion, as a regular ol’ lady on the Internet, this simplified version doesn’t seem to work. But telling you my recipe didn’t work without actually sharing what I did doesn’t seem particularly useful. So… recipe details are included.

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!

Update: We eventually resolved our fungus gnat issue. First, I watered the plants as infrequently as possible (without killing them) to limit the moisture in the soil that attracted the gnats. I also sprinkled food-grade Diatomaceous Earth on the soil of each plant to help get rid of fungus gnats. Many readers recommended it, and it worked quite well.

Then, I placed these glue board traps near the plants. They caught a lot of fungus gnats to slow the reproduction cycle. Be careful with these traps. They are incredibly sticky, as you can imagine, so keep them away from children and other small animals.

Why Would Banana Compost Tea Fertilizer Even Work?

In retrospect, and after doing quite a bit more research, I applied my knowledge of composting to this experiment. I’m not a scientist or compost expert, 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.

Additionally, I followed up my experience by reading the book Compost Teas For The Organic Grower by Eric Fisher. Despite going into great detail about many types of compost teas, different aeration systems and recipes, and a whole lot more information about why various types of compost tea are best for certain gardening situations, the author never mentions banana peel compost tea. In fact, he doesn’t even mention bananas in the book as far as I recall. If banana peel compost tea is so great, wouldn’t it have been in a book like this?

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)!

I’m being a little dramatic, of course, by saying that it’s pointless. Some plants need a lot of potassium and might benefit from an occasional potassium punch in addition to general fertilization. But I don’t think banana peel compost tea, at least as seen on social media, is the answer.

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. However, I have yet to see any decent research that shows banana peel compost tea being any more effective than compost, aerated compost teas, or even water. If you have seen such research, I’d be stoked if you could link to it or share it in the comments. I’d love to read about it.

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!

Did you make this project?

Please leave a comment on the blog or share a photo on Pinterest

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39 Comments

  1. 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

    1. 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!

  2. 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.)

  3. Banana as a whole for a smoothie is better than peeled one. Forget peeled bananas and enjoy a smoothie with a full richness of these bananas.

  4. Well one way of fighting off many insects. Is diatomaceous earth. Unknown to many you can use diatomaceous earth in water. Spray your plants good but not dripping. When it dries it will help fight off pesky insects. You can also sprinkle some on the top soil. Nematodes will help inside the soil.

    1. Thanks! I did end up trying the diatomaceous earth and it was helpful. I haven’t tried using it in water and spraying the plants. Thanks for the suggestion. I’ll have to look into nematodes as well.

  5. The ratio used to perform the banana peel tea is wrong… 5 banana peels per plant (large sized plants on 5 gallon buckets) per 1 liter of water.
    Filter it like you filter tea before drinking it or use coffee filter paper (takes time performs better).
    Use neem oil to fix the fungus gnat issue. 2% neem oil emulsified with organic castille soap and per 1 liter of water. Apply on potting soil instead of watering the plants. Perform it 1 full month and bye bye fungus gnats…

    Banana peel tea is usefull for heavy feeder edible producing plants like peppers, hot peppers, tomatoes, okras, etc. It helps on developing tons of flowers, fruits, and also on general plant health because of magnesium but gotta balance things with extra calcium otherwise you screw up the full nutrients balance (micro and macro). Mainly it’s only Phosphorous and potassium that is on the tea.

    Pay it forward! 😉

  6. And btw, forget the jars… Use a 2 liter plastic soda bottle, washed, rinsed and reuse it all the time! And keep the tea out of oxigen and light… You want a steeped tea not a full aerobic enviroment with all kinds of micro critters around… Otherwise you pay the full price of trying to be a pennysaver! 😛

    1. Thanks for the information. I haven’t tried this way but it could be a useful alternative, though it does appear you’re using this on outdoor plants as you note large plants in 5-gallon buckets? I agree that would be a better idea. I appreciate the tips and hope they work for anyone who tries them! 🙂

  7. It could be because you used brown bananas or because of the long period of time the peels were sitting in the water. I heard a good way of getting rid of pests is neem oil.

  8. Succulents for the most part don’t flower (unless they’re really mature). I use banana tea (banana peels and distilled water) for my outdoor calla lilies and hydrangeas to encourage blooms. Potassium encourages more blooms than a nitrogen-dominant fertilizer, which encourages foliage. Also I wouldn’t use brown banana peels because ripe bananas have way more sugar than say, a yellow banana. Banana tea really does work… for flowering plants, though.

    1. That’s great that you use this for outdoor plants. I haven’t tried that yet (and I’m sure it’s better than on indoor plants). I tried it on some succulents and also on some flowering plants, but they were all indoors. Thanks for the tip on brown vs. yellow bananas. If I try this again sometime, I’ll keep that in mind.

  9. I’ve been doing a lot of reading on banana compost tea. I heard that the success all starts with which bananas you use. Most people just buy bananas, but in the case of adding to your garden, you need organic bananas. Using bananas that have been treated with insecticide with surely kill your plants, starting at the root zone, so be careful! Carcinogens are found in the pesticides n will do damage to your plants.

  10. I agree with John Doe. Most house plants are leafy and need nitrogen (plus other elements) rather than a lot of potassium. Bananas contain very little nitrogen, if any.

    Also, you don’t mention diluting the mix, so may have been too strong for your plants. I will be using it on my tomatoes and chillies as they love potassium. So, a great idea, but maybe not for indoors!

    1. Thanks for the note. Maybe I’ll try this on outdoor plants in the future. That seems to be a better solution. Also, I think that properly made banana compost tea (with aeration, proper tools, etc..) probably can be more effective. But I’m still skeptical about what I think are oversimplified methods that are getting popular on social media. Haha. Thanks for sharing your thoughts. More details and perspectives are definitely helpful.

  11. Hi Jen, my name is Michelle. I’m not really a plant person but, I know how to get rid if gnats in your home. Get some Apple Cider Vinegar, pour some in a few small bowls or like dipping dishes… just a few Tbsp, then add about 1 Tbsp of dish soap to it DON’T STIR. Place these bowls where you notice the gnats in your home, but out of the way so they won’t get spilled. The gnats will be drawn to the sweet vinegar and killed by the soap. You may have to empty and refill a couple times, but they will die and collect in the dish… you’ll see. Good Luck!!

    1. Thanks for this suggestion. I tried the ACV and that didn’t seem to attract them much. But I didn’t add dish soap. I appreciate the comment. – Jen

  12. I’ve found that putting apple cider vinegar, some dish soap and water in a glass jar (only about 1/4 to 1/3 full) with plastic wrap on top secured by a rubber band with holes poked in the plastic is the best way to get rid of gnats. They are drawn to the fermented smell of the ACV, they go through the hole to get in, the soap in the liquid traps them and they die. You can set up multiple jars since you have a bad infestation.

  13. I think your results didn’t work because…well it wasn’t done right. 1) as you noted it should have been strained.
    And 2) I have only seen that you are suppose to let it set a few hours. Not week! Obviously anything sitting that long when it’s already in a decomposing state will attach unwanted attention.

    If I was you I would try again, but maybe let the plant that you experiment on stay outside in case you still run into a gnat problem.

    1. Thanks for the note on this. I was primarily trying to replicate what I keep seeing on social media, so that’s correct that I didn’t strain it. Most posts don’t talk about that (though I agree I’m sure that would be helpful). As for only sitting for a few hours, I’d be surprised if that was enough time for the nutrients in the banana to break down and become water-soluble for the plants. But maybe it would work? Have you seen any science about this being any more effective than regular water? I’m still in search of it and have had no luck. I know there are certain types of compost tea that definitely work, I’m just not sure if bananas on a jar in a counter (for any length of time and even if strained) is the right answer. Thanks again for the note!

  14. Hi Jen! When you said your plants don’t eat bananas, you’re right, but soil does. Little house plants don’t have enough soil to “digest” all that food, hence all your gnats having a feast. I use different compost teas, blackstrap molasses, and yes, banana peels outside. My roses LOVE banana peels under their mulch, and even banana tea. Try it on outside plants, potted or in the ground. If you ever want to feed your indoor plants, maybe add a tblsp of the tea to a gallon of water. Start from there and watch how the soil utilizes it. Good luck, happy plants start with happy soil.

    1. Thank you Suzanne for this really helpful comment. I appreciate it. I may have to try this outdoors sometime. We have rose bushes as well.

  15. I just have to say there are much more variables to your problem you’ve experienced than what you’ve written to the world..
    Firstly, succulents are plants that thrive with essentially little to no nutrients and or water in the soil.. Therefore your plants never even absorbed a majority of the water you put in them and when they did it was overloaded with potassium(which usually is only a necessary additive when you have fast growing or fruiting plants). This also is the main cause of your fungus gnats problem mostly because the soil was wet plus the rotting bananas created the perfect medium for a decomposing fungal growth which in turn attracted said gnats.
    Banana compost does actually work wonders but it all depends on what your growing with it.
    No worries though because with all things perfecting something takes lots of trial and error. Banana compost tea works wonders for that stubborn flowering plant that hasn’t grown in years and provides necessary carbs for microbes in the soil to feed on thus helping your roots and plant be stronger.

    1. Hi Shaz – Thanks for the note. This is helpful. I agree there are more variables in here that I didn’t necessarily cover. I would love to see a true scientific experiment on this matter, but I’ve yet to find one. I also used it on plants other than succulents, and it didn’t seem to work well for those either (though again, not under a controlled scientific experiment). It seems like it might be an ok option for outdoor plants, though I think it needs to be made in a way that’s more specific and effective than the simple “let it sit in a jar for a few days” method that seems to be popular on social media (and the method I was intending to assess). I appreciate your comment. – Jen

  16. Actually banana peel tea works great if you apply it to plants that need the extra potassium for fruiting and flowing plants.. I’ve been growing succulents for years and have never had to use any kind of fertilizer what so ever, or for any of my house plants for that matter. That’s probably why you had issues. Tomatoes and garden vegetables would benefit from this.

    1. Thanks Jake. I used it on other plants too with not much luck. Also, I bet banana peel tea that’s made through a proper process works well. Do you have a recipe you like? I just am not quite sold that banana peels sitting in a jar for a few days breaks them down enough to do anything but maybe a more formal or involved process works better? Thanks for the note.

  17. We dried up the peels, then made a tea using boiling water. Applied to some orchids – they literally exploded with flowers. I have never seen anything like it. And no gnats. But the orchids were in proper loose bark, not in soil.

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