How to Test Soil for pH
Coffee grounds lower pH.
Wood ash increases pH.
Alkaline Test (Vinegar): Place soil in a cup, add vinegar.
Fizzing/bubbles = Alkaline soil (pH > 7).
Acidic Test (Baking Soda): If vinegar didn't fizz, add water to soil, then baking soda.
Fizzing/bubbles = Acidic soil (pH < 7).
Neutral: No reaction to either test = Neutral soil.