A. Mobile nutrients are nitrogen (N), Phosphorus (P), Potassium (K), Zinc and magnesium. These nutrients are able to move themselves within the plant to go where they are needed most. Immobile nutrients are boron(B), calcium(CA), chlorine(cl), copper(cu), Cobalt(co), silicon(SI), sulfur(S) and molybdenum(mb) are not able to move themselves within the plant. They stay in their place of origin in the older leaves causing the newer leaves to show signs of deficiency. Back To Top • Q. What is the difference between Macro and Micro nutrients? A. Macro nutrients are the elements needed by the plant the most. That is nitrogen (N), Phosphorus (P), and Potassium (K). They are the basic building block of plant growth. The micro nutrients are often referred to as trace elements. They are required in trace amounts. Back To Top • Q. What do the 3 numbers stand for in a fertilizer mix fore example 20-20-20? A. These numbers represent the percentage of nitrogen (N), Phosphorus (P) and Potassium (K).