Soil pH Amendment

The direction of the recommendation follows the sign of your pH difference: if your target pH is higher than your current pH, the soil needs to become less acidic, so agricultural lime is recommended. If your target is lower than your current pH, the soil needs to become more acidic, so elemental sulfur is recommended instead. The two amendments work in opposite directions and are never combined in the same application.

Clay particles carry a much larger negatively charged surface area than sand grains, which lets them hold far more exchangeable hydrogen and calcium ions — this is called cation exchange capacity. Raising clay's pH means displacing all of those extra hydrogen ions, not just neutralizing the soil solution, so clay soils in this calculator require roughly 3.5x the lime per pH unit that sandy soils need at the same acreage; the same logic applies to sulfur on the acidifying side, roughly 4x sand's rate.

The per-acre rate (pounds of lime or sulfur per acre) depends only on your pH difference and soil texture — it's the same whether you're treating one acre or a thousand. Total tonnage then multiplies that per-acre rate by your entered acreage, so a field twice as large needs twice the total product even though the recommended rate per acre stays identical.

Large single applications of lime or sulfur are generally discouraged even though the calculator gives you a total figure — heavy lime doses can temporarily overshoot pH or create nutrient imbalances, and sulfur needs soil microbial activity to oxidize it into the sulfuric acid that actually lowers pH, which takes months. Split heavier recommended rates into two or more applications across a season and retest before adding more.