More about pH
Al have pointed out that we shouldn't worry much about pH in our container plants - it's hard to determine as many things affect it and it's always changing.
But, some of us have water with high pH (but not alkalinity) and we see our plants suffer - changes in leaf color - from yellowing to lighter greens in some places on the leaf to losing the red backing on some plants.
In response, we often use vinegar or citric acid to lower the water pH so that the resulting soil solution is acceptable to the plant.
On another forum, someone has questioned that reducing pH would have any effect. The quote was, " What causes the pH to stabilize at neutral when you add the water to soil, is the presence of thousands of buffering sites on the humic acids in the soil that soak up the hydrogen ions from the acidic water and exchange them for other cantions, bringing the pH to whatever the buffering power of the soil is, somewhere near neutral (7.0)."
The poster is assuming a peat-based soil, which many people use.
Clearly, those of us who do this see a benefit. So, seems that the above cannot be completely correct.
I want to understand the process that takes place and none of the few plant books I have discuss it. I have tried some searches, but am using the wrong terms as I come up empty handed.
Al, I am hoping you can help me understand or point me to a resource that explains it.