TL Winslow's answer to If extra CO2 enhances plant growth, as is believed by many global heating deniers, why do no growers increase the percentage of the gas in the air in their greenhouses and polytunnels? Could this be because the claim is nonsense?

https://www.quora.com/If-extra-CO2-enhances-plant-growth-as-is-believed-by-many-global-heating-deniers-why-do-no-growers-increase-the-percentage-of-the-gas-in-the-air-in-their-greenhouses-and-polytunnels-Could-this-be-because-the-claim/answer/TL-Winslow