Plants work on a similar principle as human nutrition. CO2 in - CO2 out = weight gain. A growing plant is on average* a net absorber of carbon dioxide. * On av

Plants work on a similar principle as human nutrition. CO2 in - CO2 out = weight gain. A growing plant is on average* a net absorber of carbon dioxide. * On average, not constantly. Since they can't do photosynthesis in the dark, they release CO2 at night.