Nature and Gardening

That hasn't been our experience but the apprehension is understandable. It's certainly not advised if it's the only watering that's being done, but if the soil organic matter is present and there is supplemental water the rhizosphere is likely to face few, if any, ill effects. The final solution one achieves is essentially calcium acetate and water.

Conversationally: sometimes there can be confusion around vinegars and relative pH; while ACV has the highest pH at 5% it's really the closest to neutral ranges and the bit of buffering by CaCo3 brings it closer to 5 before the dilution. Even a 1:1 solution of water and table vinegar (with averages between 2.5 and 2.7) isn't acidic enough to cause lasting damage to plants, though it can cause leaf damage. Generally speaking it's commercial vinegar with a low of 2.2 that can cause lasting damage to a given plant when applied directly to the root zone, but in many cases that same location can be replanted within a short period due to the breakdown of the solution when acted upon by soil life. As a comparison, consider that some studies show the rain during thunderstorms to have a pH of 3.63 as compared to the non-thunderstorm average of 4.05.