Lowering Soil pH for Blueberries and Azaleas

title: "Lowering Soil pH for Blueberries and Azaleas"

Blueberries, rhododendrons, azaleas, gardenias, and mountain laurel share a requirement for acidic soil: pH 4.5 to 5.5 for blueberries, 5.0 to 5.5 for rhododendrons and azaleas. Most native soils in the Northeast are naturally acidic enough for azaleas but too high for blueberries. In the Midwest and West, native soils are often alkaline — sometimes dramatically so — and growing acid-loving plants requires active pH management.

Lowering pH is harder and slower than raising it. Lime raises pH relatively quickly; sulfur lowers it slowly, requiring months and sometimes multiple applications.

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Table of Contents

1. Why Acid-Loving Plants Fail in Neutral Soil
2. Elemental Sulfur: How It Works
3. Sulfur Application Rates
4. Acidifying Fertilizers
5. Pine Needle and Organic Acid Mulches
6. Calcareous Soils: When pH Reduction Is Limited
7. Frequently Asked Questions

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