Acidic soil is soil that has a low pH level, typically below 6.0. This type of soil can affect plant growth by limiting the availability of essential nutrients like nitrogen, phosphorus, and potassium. Certain plants, such as blueberries and azaleas, thrive in acidic conditions, while others may struggle. Acidic soil can be caused by factors such as rainfall, which leaches away basic nutrients, and the presence of organic matter. Farmers and gardeners often test soil pH to determine its acidity and may add lime to raise the pH, making it more suitable for a wider variety of plants.