Sulfur Calculator
Enter soil pH, target pH, soil texture, and area to determine how much elemental sulfur to apply safely.
From soil test results; higher organic matter needs more sulfur.
Sulfur per 100 sq ft
1.95 lb
Adjusted for soil & organic matter
Total sulfur
9.8 lb
For 500 sq ft
Applications
1
9.8 lb each · Apply every 6 mo
Application guidance
- Do not exceed 10.0 lb elemental sulfur per year for this area.
- Split applications to avoid root burn and monitor pH every 3–6 months.
- Water thoroughly after applying sulfur to activate soil bacteria.
How to Use This Calculator
Test soil pH
Use a lab or accurate probe for current pH and organic matter percentage.
Enter target pH and area
Most turf grasses prefer pH 6.0–6.5; blueberries need ~4.5–5.0.
Apply sulfur gradually
Split large amounts into multiple treatments and retest soil between applications.
Formula
Sulfur (lb/100 sq ft) = (Current pH − Target pH) × 1.5 × soil multiplier × (1 + organic% ÷ 10)
Total sulfur = lb/100 sq ft × area ÷ 100
Example: pH 7.5 → 6.5 on loam with 3% OM: (1.0 × 1.5 × 1 × 1.3) = 1.95 lb/100 sq ft. For 500 sq ft → 9.8 lb total.
Tip: For large pH drops (>1.5 units), plan sulfur additions over multiple years.
Full Description
Elemental sulfur lowers soil pH by feeding microbes that convert sulfur to sulfuric acid. This calculator adjusts sulfur needs for soil texture, organic matter, and area, giving safe application rates that prevent over-acidifying or burning roots. Use it for lawns, vegetable beds, berries, and acid-loving ornamentals.
Always retest soil between applications—pH shifts take several months. Combine sulfur treatments with compost and proper irrigation to maintain soil health.
Frequently Asked Questions
How long does sulfur take to work?
Expect 2–6 months for noticeable pH change. Warm, moist soils convert sulfur more quickly.
Can I use aluminum sulfate instead?
Yes, but use caution—aluminum can build up. Elemental sulfur is safer for long-term soil health.
What if I over-apply sulfur?
Irrigate heavily and apply lime to raise pH if needed. Over-application can harm beneficial microbes.
Do I need to till sulfur in?
Incorporating into the top 6″ speeds results, but surface applications still work with regular watering.