What do the numbers on bags of fertilizer mean?

By Grant Woods,

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Please explain the numbers on fertilizer bags. I know that the first number is nitrogen (N), the second phosphorus (P), and the third potassium (K). Does a bag labeled 5-14-42 mean it contains 8% N (5/61), 23% P (14/61), and 69% K(42/61)? Consequently, if you applied 100 lbs of 5-14-42 are you applying 8lbs of N, 23 lbs of P, and 69 lbs of K?


A bag of fertilizer labeled 5-14-42 means that for each 100 pounds of product there will be the equivalent of 5 pounds of nitrogen, 14 pounds of phosphorus, and 42 pounds of potassium.  If each bag has 50 pounds of product, then reduce those numbers by 1/2.

There’s more information at: http://www.ncagr.gov/cyber/kidswrld/plant/label.htm

Enjoy creation,


February 21, 2016