Last time I grew, I moved a standard cooler into my closet and put dry ice in it. I ran a tube from the drainage spout on the cooler. When I sniffed the edge of the tube it had a acrid odor like the burn from a soda pop. It was pretty strong I sat the cooler above my plants and let the tube hang down in between my plants. I never had a problem with condensation or anything. I have never heard of anyone else using this method and would love some input.
While there are many inefficient ways to supply co2 to your plants theres only two efficient methods. Heres a brief list of the inefficient methods that have been proved to be too little co2 in too short of time. --- Dry ice, you would need a good 15-20lbs a day to make it work well in a garden of 6+ plants. --- Vinegar drip into a pan of baking soda, too little too long to produce. --- Sugar water and yeast, too little, too long, too smelly, by product is alcohol in addition to some co2 gas. This brings us to the two efficient methods both use a tank of some sorts. If heat isnt an issue and you find it easier to refill a propane tank then go with a propane co2 generator. If heat is an issue youll have to go with a co2 cylander with a flow meter/regulator. The same setup they use to carbonate soft drinks. But in answer to your question, yes I have done it before but found it wasnt enough for my setup. While the tanks cost more than the other methods the return in efficiency far outweighs the cost. You will spend more on all the three inefficient methods to produce the same amount the tanks produce. Now how do you tell your co2 is making an impact? Simple, your plants will need water more often. A good setup with co2 will use water at least twice as fast than one without.
