How to read a fertilizer bag (and how much your yard needs)
Those three numbers are percentages. Once you know that, working out how many pounds your yard needs takes one line of math.
A bag labeled 16-4-8 is 16% nitrogen, 4% phosphorus and 8% potassium by weight. Nitrogen is the one that drives green color and growth, and it’s the number you plan around.
The one-line math
Most lawns get about 1 pound of actual nitrogen per 1,000 square feet per feeding. To find how much product that takes, divide 1 by the nitrogen percentage.
For a 16% bag: 1 ÷ 0.16 = 6.25 pounds of product per 1,000 sq ft. A 5,000 sq ft yard needs about 31 pounds. Use the calculator below with your own numbers.
Slow release vs. quick release
The bag lists how much of the nitrogen is slow-release. More slow-release means a steadier feed, less burn risk and fewer surprise growth spurts.
Phosphorus
Many established lawns don’t need extra phosphorus, and some states restrict it. A soil test tells you whether yours does.
Fertilizer calculator
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