Elemental Sulfur Soil pH Lowering Calculator
Calculate elemental sulfur product per acre to lower soil pH, based on the pH gap, soil texture and the sulfur's neutralizing effect.
How This Calculation Works
Elemental sulfur lowers pH when soil bacteria oxidize it to sulfuric acid, so the rate depends on the pH gap and soil texture. A common guide is 5 to 10 pounds per 1,000 square feet per pH unit on sandy soil and more on clay. Product pounds per acre equals the target rate, and total product is that figure times acres.
Field Calibration & Rate Reference Chart
| Analysis | Nutrient % | Target lb/ac | Product lb/ac |
|---|---|---|---|
| 46-0-0 Urea | 46 | 100 | 217 |
| 46-0-0 Urea | 46 | 120 | 261 |
| 34-0-0 AN | 34 | 100 | 294 |
| 28-0-0 UAN | 28 | 120 | 429 |
| 18-46-0 DAP | 46 | 60 | 130 |
| 11-52-0 MAP | 52 | 60 | 115 |
| 0-0-60 Potash | 60 | 80 | 133 |
| 10-10-10 | 10 | 60 | 600 |
| 19-19-19 | 19 | 80 | 421 |
| 6-4-0 Milorganite | 6 | 48 | 800 |
Common Questions
How much elemental sulfur lowers soil pH?
The rate depends on soil texture and the starting pH. A common guide is 5 to 10 pounds per 1,000 square feet per pH unit on sandy soil, with higher rates on clay. Always confirm with a soil test and retest after application.
How long does elemental sulfur take to lower pH?
It depends on soil bacteria to oxidize the sulfur to acid, so it can take several months to a year. Warm, moist, well-aerated soil speeds the process. Cold or waterlogged soils slow it dramatically.
Is elemental sulfur the same as sulfate?
No. Elemental sulfur must be oxidized by soil bacteria before it lowers pH, while sulfate sulfur is already available to plants and does not acidify the soil. Use elemental sulfur when the goal is to lower pH.
Can I over-apply elemental sulfur?
Yes, too much can drive pH below the crop's optimum and harm soil biology. Apply based on a soil test and retest before adding more. It is hard to reverse an over-application quickly.