Can You Use Banana Peels as Fertilizer?

While scrolling through Facebook, you may have stumbled upon posts touting the efficacy of banana peel water, or banana tea, with an image of a gloriously full basil plant as proof that it works wonders. 

In theory, banana water as fertilizer seems intriguing. Potassium is an essential nutrient that promotes plant growth. Many plants rely on potassium to regulate water intake and aid in photosynthesis. Banana peels are high in potassium, and by soaking them in water, the potassium in the peels will leach into the water and provide plants with supplemental fertilizer.  

In reality, there is little scientific evidence to back this theory, and many scientists caution against this process, as it can actually be detrimental to plants, not to mention its pervasive stench (rotten banana is rather putrid). To conclude, you’re better off tossing banana peels into the compost bin. 

Frequently Asked Questions

What is banana water and is it good for plants?

A new gardening fad that has been making the rounds on the Internet is banana water, but don’t be fooled by the glossy pictures. While there may be anecdotal evidence that water strained from the brownish slurry of banana peels can lead to bushier plants, it is just as likely to attract unwanted pests such as gnats. Banana water is usually made by immersing peels in water for a few days, then straining and diluting the resulting solution. It can also be quite smelly. Even without the threat of mold or pests, the smell is enough to actively deter gardeners.  

Can I grind up banana peels into powder?

A more labor-intensive variation involves grinding dehydrated banana peels into powder. This can work, but it’s not guaranteed, as it still requires microorganisms to break down the potassium (houseplants tend to suffer from microbial diversity). 

What alternatives should I use instead?

A balanced organic fertilizer is a far more efficient approach. What little potassium you may have managed to extract from banana peels wouldn’t be enough, as most plants seek a balanced fertilizer that supplies them with the primary macronutrients: Nitrogen (N), Phosphorus (P), and Potassium (K). 

Can I still use banana peels as fertilizer? 

Burying banana peels in the soil of houseplants to supply extra potassium is another gardening myth. Banana peels take a long time to decompose, and whatever nutrients are gleaned from the decayed matter would likely be insignificant. 

You may still use banana peels by adding them to the compost bin. There are many composting methods out there, but Vego recommends vermicomposting because it simplifies many of the hardships associated with traditional composting. In vermicomposting, worm composters teeming with earthworms are embedded within raised garden beds, which then deliver nutrients straight to the soil. 

Why do some gardeners’ basil plants seem fuller after the addition of banana water?

The alleged usefulness of banana peels stems from claims of fuller, larger plants. The effect isn’t purely psychological – banana peels contain a variety of water-soluble minerals – including potassium. It is entirely possible for a small amount to assimilate into the soil as the banana peel disintegrates. However, this method may also make your plants smelly and welcome a fruit fly infestation, which is why it is cautioned against. 

Other Methods to Enrich the Soil

For those that are budget conscious, there are many cost-effective ways to enrich the soil without resorting to costly soil amendments. 

1. Hugelkultur Method   

To those living in the drought-prone regions of California, their salvation lies within the hugelkultur method. Of German origin, translating to ‘mound or hill culture,’ hügelkultur is a soil building technique that repurposes dead logs, branches, other debris into comfy mounds and transforms them into vital organic matter. Gardeners usually start their hugel beds during the fall, when excess woody material is plenty, and allow it to break down over the winter months. By spring, the soil is ready to be worked for planting. 

The woody foundation acts like a sponge, soaking up and retaining water to maintain an ideal level. As the lasagna layer of plant waste decomposes, air pockets open up, creating a symbiotic biosphere of fungi, microorganisms, and insects.  

2. Vermicomposting    

It ain’t much, but it’s honest work – that’s what earthworms would say if they gained the ability of human vocalization. On the surface, worms may seem not like much of a team asset, but underneath the mycorrhizal network of the rhizosphere, they play the important role of “consumers, disintegrators, and regulators.” They modify soil structures, enhance soil microbial activities, and most notably, break down kitchen waste into rich organic matter. Compost worms (Eisenia fetida), aka “red wigglers,” are the worms commonly recruited into the composting cause. They can be easily bought online at places like Uncle Jim's Worm Farm. 

3. Layer of Mulch on Top 

One of the most important benefits of mulch is its ability to suppress and kill weeds. Anytime your mulch is looking a little raggedy, replenish it by adding a layer of mulch to your garden beds, ideally mid-spring after a light rainfall. Specific types of mulch are more suited to vegetable gardens, including organic straw mulch, which adds nutrients, insulates the soil, and combats frost heaving. 

4. Utilize Finishing Soil  

A high-quality soil preferred for planters is finishing soil – a soft, fluffy soil that emulates the dark, crumbly humus found in the upper crust of the Earth. Ideal for plants that need extra pampering, this soil gives it the additional boost they need to flourish. Use it as a topsoil for raised beds or the main ingredient in mini planters.