This sounds like the perfect gardening secret! There are actually a few classic kitchen scraps that fit this description perfectly.
Most likely, we’re talking about: onion skins (or alternatively, banana peels or coffee grounds).
Here’s an overview of which “waste” items can bring your plants to their absolute peak:
- The All-Rounder: Onion Skins (as a decoction)
Onion skins are almost always thrown away, but they’re a biological powerhouse.
Protection from Insects & Diseases: A cooled decoction of onion skins has antibacterial and antifungal properties thanks to the essential oils and sulfur compounds it contains. It repels aphids and spider mites and prevents fungal diseases.
Strengthening: They’re packed with potassium, calcium, iron, and magnesium, which boosts the plants’ immune system.
Application: Pour boiling water over a handful of peels, ideally let it steep overnight, strain, and use it to water or spray your plants.
- The Classic: Coffee Grounds
Protection: Scattered around the plant in larger quantities, the coarse texture and caffeine keep slugs and some ants away.
Strengthening: Coffee grounds are an excellent source of nitrogen, phosphorus, and potassium. They are particularly well-suited for plants that prefer slightly acidic soil (such as hydrangeas, tomatoes, or rhododendrons).
- The Potassium Booster: Banana Peels
Protection: Healthy, potassium-rich cell structure makes plants more resistant to pests and frost.
Strengthening: Banana peels provide an extremely high amount of potassium and magnesium. Simply chop them into small pieces and mix them directly into the soil or use them as “banana tea” (soak the peels in water) for watering. Roses and tomatoes especially love it.
Which of these ingredients did you have in mind, or do you have a completely different waste product ready for your plants?