Garden Help: Why does soil pH matter? Larry Figart When we are having problems with our lawns or plants, the first thing that comes to mind is often that they are caused by a pest or disease. We often overlook that it could be a problem with the soil. One of the first questions that I ask when folks come to me with a plant problem is “Do you know what the soil pH is?" Most folks know a little about pH, but not why it is so important. Soil pH is measured on a scale from 1 to 14. A pH of 7 is neutral, while a pH below 7 is acidic and a pH above 7 is alkaline. Most plants grow well with a slightly acidic pH range between 5.8 and 6.3. It is no wonder that the average soil pH in Florida is almost right in the middle at 6.1.