Quick DIY Soil pH Test: Is Your Soil Acidic or Alkaline How to Test for Acidic Soil Youll need: A scoop of soil A spoon of baking soda Water optional to moisten dry soil Instructions: Place soil in a container. Add a little water if the soil is dry. Sprinkle baking soda over the soil. Watch for fizzing. Result: If the soil fizzes, its acidic. The baking soda reacts with acidic compounds in the soil, producing carbon dioxide bubbles. How to Test for Alkaline Soil Youll need: A scoop of soil White vinegar Instructions: Place soil in a container. Pour vinegar over the soil. Watch for fizzing. Result: If the soil fizzes, its alkaline. The vinegar reacts with basic alkaline minerals like calcium carbonate, creating bubbles. What This Means for Your Garden Acidic Soil Low pH: Great for blueberries, azaleas, and potatoes. Alkaline Soil High pH: Ideal for lavender, cabbage, and many herbs. Adjust soil pH with natural amendments like lime to raise pH or sulfur/peat moss to lower pH, depending on your plant needs.