Photo: Getty Images We may earn revenue from the products available on this page and participate in affiliate programs. Learn More › Home Advice You Can Trust Tips, tricks & ideas for a better home and yard, delivered to your inbox daily. View the numbers on fertilizer packaging as similar to the nutrition information labels on the foods we eat: Separated by hyphens, the three numbers on fertilizer are required by state fertilizer labeling laws to show consumers the products’ nutrient value for plants.  These fertilizer numbers, which you’ll see written as 6-4-3, for example, are a fertilizer’s NPK numbers.…