A kitchen ingredient may contain nutrients without being a suitable ready-to-use fertiliser. The useful questions are what is available to the plant, in what amount, and what else the material changes in the pot.
Avoid adding a succession of scraps or homemade liquids because each has been described as a secret ingredient. In a container, it becomes difficult to separate nutrition from changes in moisture, decomposition and the growing medium itself.
Keep the care routine understandable
Record anything added to a pot, including commercial feeds. If a plant begins to struggle, a complete history is more useful than remembering only the last product used.
Where a suitable composting process is available, use guidance for that process instead of treating fresh scraps and finished compost as equivalent materials.
For a plant that needs feeding, a labelled fertiliser suited to that plant offers instructions you can measure and repeat. Check growing conditions first, particularly the roots, light and watering. Weak growth does not automatically mean that something nutritious must be poured into the pot today.
Related reading: Homemade Fertilisers: Materials, Preparation and Limits.