From the CO2Science Archive: Phaseolus vulgaris L. or garden beans seem to do just fine with some extra CO2 to chew on. Although in this entry there is an outlier. From 1984 to 2008 there were 24 experiments showing an average growth boost of 55.8% from an extra 300 ppm of CO2 in the air. There were 4 experiments showing an average boost of 158.3% from an extra 600 ppm in the air. But there was one study showing an extra 900 ppm actually reduced growth by 19% in an unshaded pot and another that showed it had 0% effect in a shaded pot. On balance the evidence is that extra CO2 likely boosts bean growth, at least for an extra 600 ppm, which is more than we realistically expect to add to the atmosphere anyway.