Burying banana peels feeds plants potassium (roses in particular).
Banana peels do give up their potassium quickly, but a few peels are an unknown and probably small dose, and nothing shows roses need it. If you think a plant is short of potassium, get a soil test; otherwise just compost the peels.
What is actually known
A banana peel's potassium is not locked away until the peel rots. Potassium in plant tissue is dissolved in water, so it washes out of plant residues quickly. In one study, 90% of a straw's potassium was released within three days. The weakness in the belief is the dose. Nothing we have read shows buried peels supply meaningful potassium to roses or anything else, and a soil test is how to find out whether a plant is short of it.
The evidence
Evidence: not yet confirmed. It is cited to 3 sources, which a person has yet to read.
What this rests on - 3 pointers
Potassium recycling is much more affected than P because K in plant tissue is soluble in water, because little or no K is incorporated into organic compounds, and plant P is mostly present in organic forms.
Plant residue K is predominantly present in soluble form in cell cytosol
… as 90% of total K was released by the third day of the study.
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Milpa Gardens. “Burying banana peels feeds plants potassium (roses in particular).” Evidence grade: Contested. https://milpa.garden/beliefs/banana-peels-banana-peel-fertilizer/
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