Co2??

do I need to make a co2 for my plants? I have 12 plants in my patio with a T5 light I take the plants outside and bring them back in when it get's dark so I still have lights for the plants also I have 5 plants that i'm going to start flowering I have them outside for sunlight and I'm gonna make a 4x4 tent and put the plants in for complete darkness.

you dont need co2, its good and beneficial if you have a sealed room, but only when the lights are on.

cool thanks