Originally Posted by Reckless
CO2 in a greenhouse is a terrible idea. A greenhouse needs to be ventilated otherwise it gets too humid and too hot. So you're gonna blow air into it and monitorzing CO2 levels at the same time.
Man be glad you can use the sun not a HPS aznd forget about the CO2
ive seen it done once. it was in a horticulture journal documenting the cost benifit of co2 for the production of some sort of very specific very fancy ( probably very profitable) flower. they were growing transplants during the winter through spring.
this was in holland though. quite a bit colder than most of the united states.
they were using supplemental lighting for the evenings and using biomass (wood pellets probably) and natural gas if i remember correctly. they were not anywhere near the co2 figures indoor growers like to keep though... i dont think it was even double the normal co2 levels.