In a fertilizer labeled 10-10-10, what does the middle number represent?

In a fertilizer labeled 10-10-10, what does the middle number represent?

• A. Nitrogen
• B. Phosphorus
• C. Potassium
• D. Water content

Answer: (B)

In fertilizers labeled with three numbers, those are the N-P-K values: nitrogen, phosphorus, and potassium. The middle figure represents phosphorus content. It tells you how much phosphate is in the mix (historically shown as P2O5). So a 10-10-10 label means about 10% nitrogen, 10% phosphorus (as P2O5), and 10% potassium (as K2O) by weight. Phosphorus supports root development, energy transfer within the plant, and flowering/fruiting, which is why the middle number matters. Water content is not reflected in these numbers.

In fertilizers labeled with three numbers, those are the N-P-K values: nitrogen, phosphorus, and potassium. The middle figure represents phosphorus content. It tells you how much phosphate is in the mix (historically shown as P2O5). So a 10-10-10 label means about 10% nitrogen, 10% phosphorus (as P2O5), and 10% potassium (as K2O) by weight. Phosphorus supports root development, energy transfer within the plant, and flowering/fruiting, which is why the middle number matters. Water content is not reflected in these numbers.