Fertilizer Application Rate Calculator

This tool helps you calculate how much fertilizer product to apply based on your **target nutrient amount** (e.g., from a soil test) and the **fertilizer's N-P-K analysis**.

Example: If your soil test recommends 1 lb of actual Nitrogen per 1000 sq ft, and you have a 10-10-10 fertilizer, you'd input:

  • Target N: 1 lb
  • Target Area: 1000 sq ft
  • Fertilizer N: 10%
The calculator will tell you how much of the 10-10-10 product to apply per 1000 sq ft.

1. Target Nutrient Information (from Soil Test or Recommendation)

E.g., 1 lb of Nitrogen (N), or 0.5 lb of Phosphorus (P₂O₅).
Crucial for matching with the correct N-P-K percentage.
The area over which the target nutrient amount will be spread.

2. Your Fertilizer's N-P-K Analysis (Guaranteed Analysis)

First number in N-P-K (e.g., 10 for 10-10-10).
Second number in N-P-K (e.g., 10 for 10-10-10).
Third number in N-P-K (e.g., 10 for 10-10-10).

Calculated Fertilizer Application Rate

Amount of Fertilizer Product Needed: --
Amount per 100 sq ft (for small areas): --
Amount per Acre (Approx): --

Important Considerations:

  • Soil Test is Key: Always base your target nutrient amounts on a professional soil test for best results and to avoid nutrient imbalances.
  • Over-application: Applying too much fertilizer can harm plants, lead to nutrient runoff into waterways, and waste money.
  • Spreader Calibration: This calculator tells you *how much* product. You still need to calibrate your spreader to ensure it applies that exact amount evenly.
  • Nutrient Source: This calculator assumes you're targeting one primary nutrient. If other nutrients are also deficient, you might need a different blend or separate applications.
  • Organic Fertilizers: N-P-K values for organic fertilizers can be less precise or release nutrients more slowly.
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