You see them all the time on the bag of fertilizer: three numbers along with three letters — N-P-K, but what do they mean?
These three elements are necessary for a thick, healthy lawn and the numbers correspond to the percent of nitrogen, phosphorus and potash in the product. This information is key to following lawn-care instructions from county extension offices on how many pounds to apply per square foot, so it’s important to know what you are buying.
- N stands for nitrogen, which greens up the grass and promotes overall growth. Nitrogen is always the first number in how the formula is listed on the bag of fertilizer. However, the number does not distinguish between slow-release or quick-release nitrogen, which should be listed on the label.
- P stands for phosphate, an element critical for root development. Phosphate is always the second number in how the formula is listed on the bag of fertilizer.
- K stands for potash, which supports the overall health of the plant, including cell strength and its ability to withstand drought, disease and other stresses. Potash is always the third number in how the formula is listed on the bag.
The second part of the equation is the numbers and the percentages they represent. Here’s an example:
A 36 pound bag of GreenView Fairway Formula Spring Fertilizer Weed & Feed with Crabgrass Preventer covering 10,000 sq. ft. is marked 24-2-8, which means that the product has 24 percent nitrogen (N), 2 percent phosphate (P) and 8 percent potash (K). To understand how many pounds of each nutrient are being applied to the lawn, multiply each percent by the weight of the bag —
N: 24 percent × 36 pounds = 8.64 pounds of nitrogen for 10,000 sq.ft. or 0.864 pounds of nitrogen per 1,000 sq ft.
Leading scientists recommend applying Apply 0.5 to 1 pound of nitrogen per 1,000 square feet to support spring growth and to build-up reserves for summer.
As you can see, applying the right amount of these elements can be complicated. GreenView Fairway Formula fertilizers take the guesswork and math out of the equation by delivering to your lawn the exact nutrients needed for the season. Always read and follow the label directions.
Click here for more information about fertilizer formulas and applications.