Feed the Soil
Feed the Soil not the Plant. Plant health depends on healthy roots; healthy roots depend on healthy soil for air, water and nutrients delivered in forms plants can use. Soil that is rich in organic matter, aka compost, is rich in nutrients and in the life that makes those nutrients available to the plants (bacteria, worms, etc.) .
Ornamental plants in good soil usually do not need added fertilizer, and crop plants that do need extra food need less of it when it’s released slowly by friendly soil from things such as rock powders, kelp and green manures.