I'm sorry I answered for spraying the leaves with it. I did not read your question carefully enough. Yes watering the soil with carbonated water may very well work. BTW mineral water and carbonated water are used interchangably for this purpose. One thing though carbon is processed through the stomata which is on the underside of the leaves. I'm not sure if root absorbtion is as viable.

Herbus
Herbus Reviewed by Herbus on . Watering with carbonated water really good? Or with sparkling mineral water? I read that plants love the CO2 in the stuff in the Big Book of Buds. Rating: 5