How can you bring nature to an urban audience? A project by Kevin Vega and colleagues at ETH Zürich has shown that you don’t need to bring nature to people. It’s already here. In doing so, they highlight how there’s more to urban botany than spotting plants in the city.

The core of the project was simple. If you leave a tray of bare soil out in Zürich, what turns up? Wo Samen fallen (Where Seeds Fall) recruited volunteers in 2017. They left trays in their gardens and on balconies.

“We set up the project with several key expectations,” write Vega and colleagues. “(a) The types of plants that colonized participants’ trays would be primarily wind‐dispersed ruderal species; (b) Location would matter—greater amounts of gardens and flowering green space in the surrounding of the tray would increase the number and diversity of plants that were found and—due to the nature of wind‐dispersal—trays on the ground level would have a greater chance of species colonization than those on a balcony; (c) Following their participation in the project and the associated outreach events, participants would show a greater interest in and a more positive perception of spontaneous urban species as well as the kinds of green spaces which surround their gardens.”

“We hoped to inspire questions such as: Why do we call certain species (unwanted) weeds? Why do we deliberately plant certain species? To what extent do we accept the wild life of urban species that is not planned and designed by us humans? What do these species need to live their life in our neighborhood?”

They provided participants with a plastic planter tray 39.5 × 29.5 × 9 cm in size. The volunteers filled the trays with seed-free potting soil. Any plants in the tray had to arrive from outside. “For those placed on ground level, we advised our volunteers to select a flat open‐air area protected from disturbances such as cats or lawn mowers, and we encouraged them to place chicken wire over the tops of the trays for further protection,” write the authors.