Fermented Banana Peel Liquid: Potential Value, Limitations, and Evaluation

In short: Fermented banana peel liquid is made by steeping chopped peels in water with sugar (or a microbial starter) for 2–4 weeks. Banana peel contains potassium, so the liquid works as an organic supplement, but its nutrient content is usually low and variable. Dilute about 1:20 before watering, try it on a few plants first and do not use it in place of balanced fertilizer.

Ingredients

Ingredient	Suggested amount
Ripe, clean banana peels (no mould)	1 kg
Brown sugar or molasses	100–200 g
Clean, non-chlorinated water	3–5 litres
Microbial starter (optional)	As labelled
Plastic container with lid	5–10 litres

Method

1. Rinse peels and cut into 2–3 cm pieces.
2. Dissolve sugar in water, add peels and starter, leaving a quarter of the container empty.
3. Close the lid and release gas daily in the first week.
4. Keep in a cool, shaded place for 2–4 weeks, stirring every 2–3 days.
5. It is ready when it smells mildly sour like vinegar, not putrid. Strain; add the solids to your compost.

How to use it

• Dilute about 1:20 and water the soil every 1–2 weeks.
• Do not spray concentrated liquid on leaves – it can scorch.
• Use within 1–2 months; store cool.

Can it replace fertilizer?

No. Potassium content is low and varies between batches. It is a way to reuse waste as an organic supplement; plants still need fertilizer matched to their needs – see the mint feeding schedule.

FAQ

What if it smells foul?

A putrid smell means the fermentation went wrong (often too little sugar or dirty material). Discard and start again.

Is plain banana peel water good enough?

It can be used, but contains very little nutrition. Fermenting with sugar and microbes gives a more consistent liquid.

References: Ask Extension – banana peel water as fertilizer.

Further reading

• Fermented fish liquid fertilizer
• Home composting: a 30-day framework
• Organic mint: the three-pillar model