what does NPK do for plants
What Do the Numbers on Fertilizer Mean? The three numbers on fertilizer represents the value of the three macro-nutrients used by plants. These macro-nutrients are nitrogen (N), phosphorus (P) and potassium (K) or NPK for short.The higher the number, the more concentrated the nutrient is in the fertilizer.For example, numbers on fertilizer listed as 20-5-5 has four times more nitrogen in it than phosphorus and potassium.hat Do the Numbers on Fertilizer Mean? The three numbers on fertilizer represents the value of the three macro-nutrients used by plants. These macro-nutrients are nitrogen (N), phosphorus (P) and potassium (K) or NPK for short.