As plants grow, they draw upon air, water, and soil to take up the nutrients they require to support photosynthesis and the production of simple & complex sugars, amino acids, and eventually refined essential oils at peak health. The level of nutrition available in a plant is directly related to the soil's mineral content.
Nutrients consumed by plants need to be replaced in a balanced way so as to sustainably support the amazing bacterial and fungal ecosystems in the soil that form the foundation for the "web of life".