Soil pH Adjustment Calculator — Lime & Sulphur Rates
Calculate how much lime or sulphur to add to reach your target soil pH.
How We Calculate This
This calculator uses standard amendment rates per pH unit change for different soil types.
To raise pH (add lime): Sandy soil: 100g/m² per pH unit. Loam: 200g/m². Clay: 300g/m².
To lower pH (add sulphur): Sandy soil: 25g/m² per pH unit. Loam: 50g/m². Clay: 75g/m².
Clay soils need more amendment because they have greater buffering capacity.
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.