What Is the Meaning of Optimum PH?

Achieve optimum soil pH.

According to Clemson University Extension Service, most common garden plants thrive in a slightly acidic soil, with a pH ranging from 5.8 to 7.0. Gardeners can test their soil pH with a home testing kit and take steps to adjust the soil to an optimum pH.

Definition of pH

Horticulturists measure soil acidity and alkalinity by the pH scale. A ranking of 7 on the pH scale is a neutral pH. Any pH between 0 and 7 indicates an acid soil, and any pH from 7 to 13 indicates alkaline conditions.

Significance of Optimum pH

A soil with a strong acidic pH won't support the beneficial bacteria that break down organic matter into humus. A soil with a high alkaline pH decreases the ability of plants to use available nutrients in the soil and causes the soil structure to break down.

Factors Affecting pH

Gardens that receive excessive rainfall or irrigation have soils that acidify quickly, as the water leaches through the soil. Overly dry conditions can contribute to alkaline soils, as evaporation contributes to the buildup of alkaline salts.

Achieving Optimum pH

Gardeners with acidic soil can increase the alkalinity with fireplace ashes or an application of limestone. Gardeners with alkaline soil can add peat moss, sulfur or aluminum sulfate to the soil.

Warnings

Gardeners must take care when adding materials to correct soil pH. Like adding too much salt to your soup, it's easy to add a bit of soil-correcting agents at a time but impossible to remove too much.

References

• Clemson University Extension Service: Soil pH
• Rodale, R. (1999). The Encyclopedia of Organic Gardening. Rodale Books, Inc: Emmaus, PA.