To put some math around CO2 usage:

The entire structure of plants is built primarily from CO2. A tomato plant and fruit grows from seeding to maturity in about 60 days, and will yield about a kilogram of dry plant mass.

That mass will be about 20% carbon, meaning each plant would need to uptake a net 3.3 grams of carbon - 12.3 grams of CO2 per day. A person exhales around 1Kg of CO2 per day, or about as much as would be needed to supply 81 tomato plants.