Fertilizer Calculator

Calculate exactly how much fertilizer your lawn or field needs based on nutrient targets.

Application Goals

Total Area

Unit

Desired Rate (N)

Nutrient

Basis: lbs per 1,000 sq ft

Fertilizer Grade

Nitrogen N

Phosphate P

Potash K

Application Summary

Enter area and rate

Overview

Fertilizer labels (e.g., 10-10-10) represent the percentage by weight of Nitrogen (N), Phosphate (P₂O₅), and Potash (K₂O). The remainder is filler material for even spreading.

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Pro Tips

Lawn Health: Most lawns primarily need Nitrogen for green growth and density.
Soil Testing: Only apply Phosphorus if a soil test indicates a deficiency to prevent water runoff pollution.
Timing: Apply fertilizers when the grass is actively growing and soil moisture is adequate.
Uniformity: Use a calibrated spreader to ensure even distribution of nutrients.

Fun Facts

"The 'N-P-K' numbers (like 10-10-10) are percentages by weight. A 50lb bag of 10-10-10 contains 5lbs of actual Nitrogen."
"Historically, crushed bones were used as fertilizer for their Phosphorous content."
"Nitrogen promotes green, leafy growth (Blade). Phosphorus promotes roots and fruits (Root). Potassium promotes overall hardiness (Health)."
"Lawns often need a 4:1:2 ratio, while flowering gardens might prefer 1:2:1 to encourage blooms."

Formula: Weight Needed = (Target Rate / (Percent Nutrient / 100)) × Area

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