Another popular approach you may have heard about is to soak banana peels to make a sort of compost tea or banana water to be used as fertilizer. We hate to break it to you, but this doesn’t work either! “Any sort of compost tea is worthless,” says Chalker-Scott. “There are zero studies that show compost tea has a consistent positive effect. One study looked at the impact of compost tea on soil chemistry, such as the pH and nutrient content, and found it was no better than plain water.”
Banana peels actually could hurt your plants.
When buried, banana peels are slow to decompose. “You should have a balanced micro-organism environment in soil,” says Sam Schmitz, horticulturalist and supervisor of grounds operations at Ball Horticultural Company. “If other fungi are present in the soil, they could break down the peels and release non-beneficial chemicals that could start attacking living plant tissue.” You’re not much better off using it on plants indoors either, because rotting peels could attract pests such as fruit flies or may trigger smelly mold growth—neither of which is a pleasant experience. Finally, you have no idea if the peels contain pesticide residues, which could damage your plants.
But what about all the gardeners who say banana peels are good for plants?
In a nutshell, it’s all anecdotal evidence, not science-based studies that claim banana peels are good for plants. “One person’s experience with one or two plants doesn’t prove anything because the data size is too small,” says Schmitz.
What other organic fertilizer should I use?
“If you do want to feed your plants, you don’t have to experiment,” says Habteselassie. “Organic fertilizers are a known entity.” Look for those with the Organic Materials Review Institute (OMRI) seal, which ensures the product’s ingredients are in compliance with organic production methods.
Side note: It’s worth mentioning that organic fertilizers can be smelly because they’re derived from plant and animal sources. While the odor fades, pets may be attracted to both liquid and granular types. In fact, organic fertilizers regularly make ASPCA’s list of top 10 toxins because they can cause vomiting, tummy upset, and seizures if ingested. Keep your fur babies safe by fencing in your garden, keeping potted plants out of reach, and not leaving organic fertilizer or any other garden products where pets can get to them.