Zone Forge reads your Illinois soil test in Illinois's own calibrated language — the critical levels and rate logic come straight from Illinois Agronomy Handbook — Chapter 8 (Managing Soil pH and Crop Nutrients), not a national average.
Published source: Illinois Agronomy Handbook — Chapter 8 (Managing Soil pH and Crop Nutrients)
Illinois Agronomy Handbook — Chapter 8 (Managing Soil pH and Crop Nutrients). Zone Forge cites the publication on every recommendation.
Yes — the Illinois soil-test recommendation calculator is free and needs no signup. Enter your lab values for source-cited P, K and lime guidance.
Zone Forge reads every Illinois soil test in its own state's language, then builds source-cited fertilizer and lime recommendations and full variable-rate prescriptions. See the science →