The pH value determines the extent to which nutrients and trace elements are dissolved and available to plants. Optimizing the pH is therefore often more effective than additional mineral fertilization. With increasing land use intensity, the pH value should ideally be in the optimal range of around 6.2. The frequently cited lower limits of pH 5.0 (light soils) or 5.5 (heavy soils) should be understood as absolute minimums and should not be targeted. Even extensively managed, species-rich meadows benefit from pH values around 6.2.
Calcium plays a key role: it not only influences the pH value, but also ensures a stable soil structure, promotes the formation of a crumbly texture, and improves aeration. Soil life also benefits from this – earthworms, in particular, find better living conditions in well-structured soils.
On this topic, Walter Starz gave a lecture on January 19, 2026, as part of the online organic farming roundtable of Bio Austria and the Vorarlberg Chamber of Agriculture.
You can listen to and watch it here.
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