You are doing it wrong. Here’s what fertilizer to use on what houseplants

7. 🧅 Onion Skin Tea
Why: Natural source of potassium, calcium, and sulfur.
How to Use: Boil 1 cup of onion skins in 1 quart of water, let steep overnight, cool, and strain. Use once a month as a foliar spray or root drench.
Best Used On: Peace Lily, Bird of Paradise, Orchids.
Avoid On: Ferns, Calatheas—sensitive to strong-smelling fertilizers.