Eggshells, coffee grounds, and banana peels are often promoted as easy homemade fertilisers. Social media videos may suggest placing them directly into pots or turning them into special plant drinks. These kitchen scraps can be useful, but they are not instant, balanced fertilisers. Their benefits depend on how they are prepared, how much is used, and whether they are composted properly.
Eggshells contain calcium, but they break down very slowly. Large pieces placed on top of the soil may remain there for a long time without releasing much calcium to the plant. Washing, drying, and crushing them into a fine powder can help them break down faster, but the effect is still gradual. Eggshells are best added to compost rather than treated as an immediate solution for calcium deficiency.
Used coffee grounds contain organic matter and small amounts of nutrients. However, adding thick layers directly around plants can cause the grounds to compact, reduce airflow, and hold too much moisture. They may also encourage mould when kept constantly wet. A safer approach is to mix a small quantity into a balanced compost pile with dried leaves, cardboard, and other materials.
Banana peels contain potassium and other nutrients, but placing whole peels directly into pots can attract flies, ants, or other pests. They may also smell while decomposing and can disturb the soil around plant roots. Banana-peel water is popular, but it does not provide complete plant nutrition and its strength is difficult to measure. Composting the peels is generally more practical and reliable.
The main problem with relying on one kitchen scrap is that plants need a range of nutrients. Calcium, potassium, or nitrogen alone cannot replace balanced soil care. Plants also require suitable light, watering, drainage, root space, and sometimes a properly formulated fertiliser.
The best way to use these materials is to combine them in a well-managed compost system. Mix wet kitchen scraps with dry brown materials, maintain airflow, and allow everything to break down fully. Finished compost is safer, more stable, and easier for the garden to benefit from.
At the end of the day, eggshells, coffee grounds, and banana peels can help plants, but not as overnight miracle treatments. Compost them, use them in moderation, and avoid placing large amounts of fresh waste directly into pots.
If you are reusing kitchen scraps in your home garden, we would love to see what you are trying. Tag @projectharvest.my on Instagram and share your composting experiments, plant progress, and gardening journey with us — your experience might help another Malaysian beginner separate useful garden habits from common myths too.