Soil pH Correction (Lime) Calculator

Work out soil ph correction (lime) instantly with clear inputs, formula shown and shareable results.

About Soil pH Correction (Lime) Calculator

Lime requirement scales with the pH rise wanted and with the soil's buffering capacity: a sandy soil needs roughly 1.2 t/ha of agricultural lime per pH unit, a loam 2.2 and a clay or high-organic-matter soil 3.5. Where more than about 4 t/ha is indicated, split it across two seasons and re-test rather than applying it all at once.

Formula

Lime requirement

Lime (t/ha) = (target pH - current pH) x buffering factor (sand 1.2, loam 2.2, clay 3.5)

Worked example

With the default values below, Soil pH Correction (Lime) Calculator returns Lime Requirement of 2.86. Change any input above and every figure here is recalculated in your browser.

Inputs used

Current Soil pHaccepts 3–8: 5.2
Target Soil pHaccepts 4–8: 6.5
Soil Textureone of Sandy, Loam, Clay / high organic matter: Loam
Areaminimum 0.01 ha: 2 ha

Results

Lime Requirement: 2.86
Total Lime Required: 5.72
pH Rise Targeted: 1.30
First Application (half dose): 2.86

Step by step

1Values used
2Lime requirement
3Lime Requirement= 2.86
4Total Lime Required= 5.72
5pH Rise Targeted= 1.30
6First Application (half dose)= 2.86

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How long does lime take to work?

Finely ground lime incorporated into moist soil shifts pH measurably in 3-6 months and reaches full effect in 12-18 months. Surface-applied lime on no-till land is much slower.

Is dolomite better than calcitic lime?

Dolomite supplies magnesium as well as calcium and is the better choice where a soil test shows low magnesium. On soils already high in magnesium, use calcitic lime to avoid imbalance.