Lawn Fertilizer Calculator
Determine exact fertilizer bag weight to apply 0.5 to 1.0 lb of nitrogen per 1,000 square feet.
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How to Calculate Fertilizer Rates for Turfgrass
Fertilizer bags display three numbers representing percentage by weight of Nitrogen (N), Phosphate (P₂O₅), and Potash (K₂O). For example, a 24-0-8 bag contains 24% nitrogen.
Lbs Product / 1,000 sq ft = Target Lbs Nitrogen / (Nitrogen % / 100)
Total Product = (Lbs Product / 1,000 sq ft) × (Total Lawn Sq Ft / 1,000)
If your target is 0.75 lb N using 24-0-8: 0.75 / 0.24 = 3.125 lbs of fertilizer product per 1,000 sq ft. For a 5,000 sq ft lawn, you need exactly 3.125 × 5 = 15.6 lbs.
Frequently Asked Questions
How many pounds of nitrogen per 1,000 sq ft per year does a lawn need?
Cool-season grasses (Kentucky Bluegrass, Tall Fescue) typically require 2 to 3 lbs of N per 1,000 sq ft per year. Warm-season Bermuda can use up to 3 to 4 lbs, while Zoysia needs 1.5 to 2.5 lbs.
Why does my fertilizer have 0% phosphorus?
Many states and municipalities ban lawn fertilizers containing phosphorus unless establishing new sod or seeding, because excess phosphorus runoff triggers toxic algae blooms in lakes and streams.
How do I calibrate my broadcast spreader?
Weigh out enough product for 1,000 sq ft, mark off a 50 ft by 20 ft test strip, and adjust your spreader gate until the measured amount covers the area evenly.