IamAloser

First of all, let me say that spraying your plants with almost any carbonated beverage is a bad idea. Most beverages are carbonated with a chemical called carbonic acid. Spraying a plant with acids of any kind is a bad idea. Also, most of them will dry and leave some type of residue that will clog thepores of a plant. Spraying also increases humidity, which is a great idea if you want your plant to make skimpy amounts of resin and possibly catch rot. Besides that, just spraying a little club soda is about as efficient as just breathing on your plants for a few seconds.

But wait! Theres a better idea!

Go to your local supermarket and look in the health section. You should be able to find a very cheap vaporizer that lets you hook up a bottle to it. Put a bottle of club soda or something similar into it and you will have a nice CO2 generator. Put a few rags over the place where the vapor comes out so you stop moisture from rasing humidity. Make sure and change the rags very often and dry them out elsewhere. This works very well in closed areas and is much cheaper than buying a large CO2 tank complete with timer etc.