For example, an apple tree can still thrive in clay soil as ... slightly acidic range from around 6 to 7.5. To test the pH, gather soil samples and use a test kit from a gardening store.

However, a slightly alkaline (pH 7.4-7.8) or higher pH soil can cause a problem with the availability of iron to pin oak and a few other trees in Central New York causing chlorosis of the leaves which ...