These three numbers represent the content of primary nutrients in the fertilizer formulation nitrogen, phosphorus and potassium. Fertilizer 13-13-13 is a general purpose, quick release product that must be reapplied frequently to be effective.
![](http://clemmonshamnerseed.com/wp-content/uploads/2018/06/FERTILIZER-13-13-13.jpg)
These three numbers represent the content of primary nutrients in the fertilizer formulation nitrogen, phosphorus and potassium. Fertilizer 13-13-13 is a general purpose, quick release product that must be reapplied frequently to be effective.