This Berlin App Lets You Adopt a City Tree and Water It Like a Pet

Berlin has around 900,000 street trees, and an open-source app called Gieß den Kiez is turning them into a citywide pet project. You pick a tree, it shows up as a pin on the map, and the app sends you real-time watering instructions based on the tree’s species, age, weather, and location. When a tree is thirsty, it turns orange or red, and icons on the map point you to the nearest public water tap so you can actually do something about it.

Launched in 2020 by CityLAB Berlin, the app gained serious traction during COVID lockdowns, when everyone wanted an excuse to get outside and a small, satisfying task with visible results. One Berlin user told the Guardian that it“feels very fun, almost like a video game,”and also explained the real barrier it removes: lots of people are happy to water a tree, but they aren’t sure if it’s their responsibility or if it would look strange. The app answers both. Potsdam, Leipzig, Magdeburg, and Paris’s 17th arrondissement have already created their own versions.

The stakes keep rising, too. Berlin hit over 103 degrees Fahrenheit this summer, and urban trees are increasingly treated as critical infrastructure that lowers street temperatures and public health risks, not just neighborhood decoration. That’s what makes a scrappy civic-tech tool like this one worth watching for any city facing hotter summers.

Would you adopt a tree in your neighborhood? Tell us which one you’d pick.