CO2: too little gas in the greenhouse

Autumn red peaches

The term greenhouse gas is a strange one for gardeners and horticulturists because plants absorb CO2 and dispel oxygen. Thus a big problem with greenhouses is that there is too little CO2 and too much oxygen. Does this mean that shoppers at commercial greenhouses are more likely to buy things? Probably not. There is even an urban myth that claims that casino owners pump oxygen inside their establishments.

A Chinese study has shown how increasing CO2 inside greenhouses used to grow peach trees in China has greatly increased the quality of the fruit.

Of course, while CO2 is great for plants, it's not so great for humans. We think that CO2 is bad and oxygen is good. In fact, there is quite the market for oxygen for human-use. But oxygen is not as benign as you might think. We need a certain amount of oxygen, but not too much.

Compare the figures given in the above links to the amounts of CO2 in earth's atmosphere over time. I suppose the lesson should be "everything in moderation".