What is Soil Acidity? Soil acidity, also known as soil pH, refers to the level of acidity or alkalinity in the soil. The pH scale ranges from 0 to 14, with 7 being neutral. A pH below 7 indicates acidic soil, while a pH above 7 indicates alkaline soil. Most plants prefer a slightly acidic to neutral pH range for optimal growth.
Why is Soil pH Important? Soil pH plays a crucial role in plant health and nutrient availability. It affects the solubility of essential nutrients in the soil. When soil is too acidic or too alkaline, certain nutrients may become less available to plants, leading to nutrient deficiencies and poor growth.
How to Test Soil pH: There are several methods to test soil pH, ranging from DIY kits to professional laboratory tests. Here are some common ways to determine soil acidity:
- Soil pH Test Kits: Soil pH test kits are readily available at garden centers. They usually consist of test strips or a liquid solution that changes color based on the soil pH. Follow the kit’s instructions to collect a soil sample and perform the test.
- Digital pH Meters: Digital pH meters provide more accurate readings than test kits. Insert the meter’s probe into a soil sample, and it will display the pH level.
- Laboratory Testing: Some agricultural extension offices and private laboratories offer soil testing services. They can provide a comprehensive analysis of soil nutrients, including pH.
- pH below 7: Acidic soil. Plants like blueberries, azaleas, and rhododendrons prefer acidic soil.
- pH around 7: Neutral soil. Many vegetables and ornamental plants grow well in this range.
- pH above 7: Alkaline soil. Plants like lilacs and certain grasses thrive in alkaline conditions.
- Raising Soil pH (Alkaline Soil):
- Add Agricultural Lime: Incorporate agricultural lime into the soil to raise pH gradually. Follow the recommended application rate based on the soil test results.
- Use Wood Ash: Wood ash from hardwood fires can also increase soil pH. However, avoid using it around acid-loving plants.
- Lowering Soil pH (Acidic Soil):
- Add Sulfur: Elemental sulfur can be used to lower pH gradually. It’s available in different forms, such as powdered or pelleted sulfur. Follow the application rate based on the soil test results.
- Use Acidifying Fertilizers: Certain fertilizers formulated for acid-loving plants, like ammonium sulfate, can help lower soil pH.
- Slow and Steady: Whether raising or lowering pH, it’s crucial to do so gradually. Drastic pH changes can harm plants.
- Re-Test: After amending the soil, re-test the pH to ensure it has reached the desired range.
