Get a bottle of carbonated water, put in a spray bottle, and spray your plants. Your plants will receive CO2 from the carbonation, and it is cheap and safe.
serpentine5 Reviewed by serpentine5 on . First Timer...PLEASE HELP!!! since dry ice is compressed, frozen CO2, would it be safe to put some dry ice on top of my medium so that it melts and releases the CO2 around the plant? Just thought it could be a cheap source of CO2. All suggestions are appreciated:rastasmoke: Rating: 5