You can test your soil pH with a soil-testing kit, available from garden centres.
Remove a small handful of soil from the area to be tested and add it to the test tube provided. Then add the soil-test powder included in the kit.
Next, add distilled water to the soil and the test powder, filling up to the level marked on the side of the test tube
Secure the lid and shake the test tube. Wait a few seconds for the liquid to change colour, then compare it with the pH colour chart supplied.
A yellow or orange liquid indicates an acid soil, bright green indicates a neutral one, and dark green indicates an alkaline soil.