Understanding NPK: The Three Key Nutrients in Fertilizers When you look at a fertilizer label, you'll often see three numbers. These numbers stand for nitrogen (N), phosphorus (P), and potassium (K). Each Lettuce Nutrient Npk A 8 0 0 E B 0 6 12 Liquid 10 10 10 NPK Fertilizer, Balanced Liquid Concentrate Fertilizer for Lawns & Plants 2.5 Gallons Liquid Fertilizer Concentrate 18 6 12 Water Soluble Lawn Food: 16 4 8 Complete Balanced NPK (32 ounce) 30 0 0 NPK Liquid Fertilizer Lawn Food: 16 4 8 Complete Balanced NPK (32 ounce) Bulletin E 3507 Introduction to Fertilizer Planning for Vegetables Developing and Educating Managers and New Decision makers (DEMaND)