Using seltzer water to enrich plants with CO2 is only feasible for small plants such as seedlings or clones. If large plants were sprayed it would raise the humidity of the space to unacceptable levels and it would be an expensive way to deliver CO2 as compared with a tank or CO2 generator.
As the seltzer evaporates, the CO2 does too and is absorbed into the leaves through the stomata (plant pores). The rate of evaporation is controlled by the temperature, the humidity and the breeze. Once the water has evaporated, wait five to 10 minutes before spraying again. It’s probably inconvenient for you to spray the plants every half hour or so. Even an occasional spritz will increase the photosynthesis rate for 20-30 minutes. A few spritzes a day will increase the growth rate a bit.
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