Can't Find the Exact Fertilizer Your Soil Test Recommends? Here's How to Substitute

When the Store Doesn't Carry Your Prescribed Fertilizer Analysis

Your UGA soil test calls for 15-0-15 in spring and 34-0-0 in summer—but local retailers stock neither. A recent survey of a big-box store and a major garden center revealed 36 different fertilizer analyses, yet these two common recommendations were absent. Don't panic: smart substitution gets you the same results.

Spring Substitute: 10-0-6 Instead of 15-0-15

Since 10-0-6 has two-thirds the nitrogen and potassium of 15-0-15, simply apply 1.5 times the recommended rate. If your report says 10 lbs per 1,000 sq ft of 15-0-15, use 15 lbs of 10-0-6. Nutrient delivery matches almost perfectly.

Summer Substitute: 35-0-5 Instead of 34-0-0

The 35-0-5 analysis is close enough to 34-0-0 that you can apply the exact same amount specified in your soil test. The small phosphorus and potassium addition won't harm established turf.

Calculate Any Substitution Yourself

A handy calculator and full list of locally available analyses are available at bit.ly/UGAfert. Enter your target analysis and the products you find; the tool computes the adjusted rate instantly.

Key principle: match the nitrogen rate first, then accept minor differences in phosphorus and potassium. Your lawn gets what it needs without the search frustration.