Abstract

Techniques and tools reduce pH drift downward in growth media triggered by plant growth or ammoniated fertilizers. Methods and compositions provide growing media with buffering potential to prevent pH drifts in the growing media. A compost composition has a buffering potential against pH changes. A carbonate index test provides information on a buffering potential of a compost composition. A growing medium includes a compost composition with a buffering potential to provide a stable pH that is conducive to plant growth in the growing medium.