DIY test for acidic or alkaline soil. 1.Scoop some soil into a container. Then, add a half-cup of vinegar. If the soil bubbles or fizzes, it's alkaline. 2. If there's no reaction, scoop a fresh soil sample into a second container. Add a half-cup of water and mix. Then, add a half-cup of baking soda. If the soil bubbles or fizzes the soil is highly acidic.
Or you can use this Innovative and inexpensive soil test kit. It Contains tests for ph, nitrogen, phosphorus, and potassium levels; 40 tests in total. Also has a chart of pH and NPK levels for more than 100 plants. Includes complete instructions for adjusting soil conditions.