Yellowing leaves? Use Micro-Elements Mix! For healthy growth, plants need food. While macro-nutrients (Nitrogen, Phosphorous, Potassium) are present in all fertilizers (N-P-K ratio), micro-elements ( Boron, Iron, Magnesium, Zinc, etc.) are often missing or unavailable to plants. One of the symptoms of micro-element deficiency is chlorosis or yellowing between the veins of leaves. Foliar sprays can help fix the problem very quickly! Read more... See instructions here