About the episode
How do we keep cities green, make better use of the space on our roofs and ensure we get enough food? Researchers from the United States believe that through smarter use of air coming from ventilation systems.
Roof gardens do exist, of course, but the plants that grow there have to contend with more radiation from the sun, more wind and less moisture due to the substrate they are in. This results in less healthy and smaller plants. That’s why they looked at the rooftop of Boston University to see if they could do something about it.
The test was performed with spinach and corn. This method is planned so that the air from the ventilation system – which has a higher concentration of carbon dioxide – can reach the plants well. As it was expected that spinach would do well there, maize was used as a control plant to check if the use of ventilation air might also have other consequences for plants.
During the experiment, things like plant size, number of leaves, total biomass were measured and what they saw: ventilated spinach had four times more biomass than unventilated spinach.
Now there are still a number of things to investigate, for example the ideal flow rate of air. Also, biomass doesn’t say everything: don’t we just want to capture CO2? Instead of pumping air through the vegetable garden? But until then, it might not hurt to try it – where possible.
Read more: Penetrating carbon dioxide ventilation can turn city rooftops into shock-absorbing botanical gardens
