Nutrition & Root-Zone Chemistry
pH, Alkalinity & Root-Zone Buffering
pH describes hydrogen-ion activity at a moment in time, while alkalinity describes acid-neutralizing capacity. Source-water alkalinity, media chemistry, fertilizer form, and biological activity can therefore drive root-zone pH over time.
Key concepts
- pH and alkalinity are different measurements
- Water with similar pH can have very different buffering capacity
- Media and irrigation frequency influence how chemistry accumulates
- pH adjustment without alkalinity context can be temporary
What to measure or observe
- Measure source-water pH and alkalinity when possible
- Track root-zone pH trends rather than one isolated reading
- Record fertilizer and acid/base additions
- Compare input and representative root-zone measurements
Common mistakes
- Using source-water pH alone to judge buffering
- Chasing every small pH change
- Ignoring alkalinity in repeated irrigation
- Assuming runoff pH perfectly represents the whole root zone
Visuals this lesson still needs
- pH-versus-alkalinity diagram
- Root-zone buffering flow
- Repeated-irrigation chemistry timeline
- Input-to-root-zone comparison