Bananas are one of the most popular fruits in the United States. But after eating the banana, you're left with the banana peel which, unless it is composted, it ends up in the household garbage and eventually in a landfill. Some ideas about re-purposing banana peels have surfaced and one of these ideas includes making banana water from the peels for use as a plant fertilizer. While the intention is laudable, it is a questionable gardening practice. Not only are the benefits not supported by science and research, banana water can actually harm your plants.
Here's what we've learned about banana water including why it can do more harm than good, along with some tips about composting banana peels.
What Is Banana Water?
Banana water is similar to compost tea but it comes only from one source, cut up banana peels. The peels are immersed in water and steeped for anywhere from one hour up to a few days. Soaking time varies according to different recipe sources. Some instructions even tell you to keep a pitcher with banana water in your fridge and add more banana peels over several weeks. After the recommended amount of time, the liquid is then strained and added to plants as a fertilizer.
Suggestions include using banana water both for house plants and outdoor plants. Some instructions include aeration to prevent the peels from fermenting. But is banana water good for plants? Here is what we found out.
Is Banana Water Good for Plants?
Bananas are touted for being rich in potassium even though their potassium content is not particularly high. Other fruits and vegetables such as kiwis, acorn squash, and avocados are richer in potassium. One of the three macronutrients crucial for plant growth and reproduction, potassium (K) is also referred to as the nutrient that ensures plant quality. Potassium in plants improves resistance to drought or excess water, extreme temperature fluctuations, pests, diseases, and nematodes.
The main problem with banana water is that soaking the peels does not extract potassium to make it available to the plants. Plants can only absorb nutrients that have been broken down by microbes and fungi. Like most raw materials, banana peels should be composted because the process of decomposition is a necessary step for release of the beneficial nutrients. Water, by itself, is insufficient for releasing the potassium.
How Banana Water Can Harm Plants
Adding banana water to your plants may actually backfire.
Most plants need a balanced fertilizer that supplies the macronutrients, nitrogen, phosphorus, and potassium. If you fertilize your plants with just banana water, they might get a tiny amount of potassium at best, but none of the other nutrients.
Banana water can also attract insects such as gnats and vinegar flies (fruit flies).
Also keep in mind that conventional banana farming is pesticide-intensive. One of the insecticides widely used in production is the neurotoxicant chlorpyrifos. The peel prevents it from getting into the edible part of the banana, which is why bananas are not listed by consumer watch groups as a pesticide contaminated food. Using banana water made from peels that have absorbed pesticide means you may be introducing those contaminants into your plants, causing an undesirable result, especially when used with edible plants and herbs.
Alternative Fertilizer Choices
Instead of taking your chances with banana water, it is best to use a commercial organic fertilizer that lists exactly which nutrients you are adding to your plants. Organic fertilizers are marked with a label from the Organic Materials Review Institute (OMRI), which makes them easy to identify.
You can also compost banana peels although they can take up to a year to break down into usable compost.
Safely Composting Banana Peels
Adding banana peels directly to the soil as in trench composting will give the same result as using banana water. Until the peels have completely broken down, any nutrients available will not be taken up by the soil or by any plants grown in it. This means waiting to plant until the raw materials have fully broken down. Unless you bury them deeply, you also risk attracting pests and rodents. Unless you plan to leave an area of your garden fallow for this purpose, there is no real benefit to trench composting as opposed to working a compost pile separate from your planting area.
Add your banana peels to your compost bin or pile or consider alternatives for indoor composting. Most pesticides licensed for use in the United States will also break down and be rendered harmless through composting. Keep in mind that most commercially grown bananas, however, are not grown in the United States, so composting organically grown peels is the safest bet.
Potassium for crop production. University of Minnesota Extension Office.
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Banana Cultivation Is Pesticide-Intensive. Environmental Working Group.
National Center for Biotechnology Information. PubChem Compound Summary for CID 2730, Chlorpyrifos. https://pubchem.ncbi.nlm.nih.gov/compound/Chlorpyrifos.
Dirty Dozen Foods. Environmental Working Group