First, measure the pH of your tap water and record it. As an example, let's say that it is 7.0, exactly neutral. Let's say that your runoff comes out at 6.5. How did that happen? The water passed through a more acidic matrix and dropped its pH. You can assume that your true soil pH is a couple tenths of a pH point lower than the runoff in this case- I'd assume about a 6.2. If it comes out HIGHER, just go in the opposite direction. If it came out 7.5, you can assume that you need to drop down from about 7.8.
@Digdug111120 edited, missed start. Taken from another site.
@Digdug111120 edited, missed start. Taken from another site.
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