It’s raining outside. So why is that city watering truck still making rounds? If you live in Poznań, you’ve probably seen this and scratched your head. But what might look like a municipal mix-up is actually a smart, science-backed decision. Poznań is one of the driest cities in Poland—and watering trees in rain turns out to be one of the best ways to help them thrive.
Not All Rain Is Equal—Especially in the City
It’s easy to assume that rainfall solves all irrigation needs. But while grass and small plants can usually ride out dry spells with what falls from the sky, street trees? Not so much.
Trees planted in city environments face a whole range of stressors—limited root space, compacted soil, higher temperatures, and less access to natural groundwater. They need deeper, more sustained hydration than a passing rainstorm can provide. Add to that Poznań’s unusually dry climate, and you’ve got a situation where even wet weather doesn’t do the job.
In 2023, Poznań recorded one of the starkest rainfall disparities in the country. The north of the city was relatively soaked, while the south and southwest were parched. The difference in total rainfall? A whopping 105 mm.
Watering Trees in Rain: Yes, It Actually Makes Sense
Here’s where it gets interesting: the ideal time to water a tree in Poznań is often when it’s already raining.
Why? Because rain moistens the top layers of the soil. This makes it easier for manually applied or system-delivered water to seep deeper into the ground—where a tree’s roots actually live. Think of it like pre-wetting a sponge before cleaning—it absorbs more efficiently.
The goal isn’t just to keep trees alive. It’s to support their long-term growth. And that means focusing on root depth and soil conditions, not just surface moisture.
explains Agnieszka Szulc, head of the Green Areas Department at Poznań’s Municipal Roads Authority.
In fact, Poznań uses smart irrigation systems equipped with sensors that monitor both rainfall and soil moisture. These are already in place in the city center—on streets like Solna, Święty Marcin, and 27 Grudnia—where greenery is more diverse and more demanding. The result? Targeted, data-informed watering that avoids waste and supports real growth.
Who’s Behind the Watering?
Watering in Poznań is handled by specialized contractors working under detailed care agreements. These professionals don’t just turn on the tap and hope for the best. They monitor plant health, check weather forecasts, and calculate when and how to water for maximum effect.
And here’s an unexpected twist: they pay for the water themselves. That’s right—contractors are financially responsible for the water they use, giving them every reason to be efficient. There’s no such thing as watering “just in case.”
Currently, more than 7,500 trees in Poznań are under this kind of expert care—mostly young trees growing in tight, challenging spots like between roads, sidewalks, or urban developments. Depending on their location and root access, some trees may need watering support for up to 10 years after planting.
Rain in a City ≠ Rain in a Forest
One reason watering trees in rain is sometimes necessary? Cities are hot. Literally.
Urban areas trap heat, creating what’s known as the urban heat island effect. Pavement, buildings, and vehicles raise the temperature, which speeds up evaporation. That means the little rain that does fall often disappears before it reaches a tree’s deeper roots.
In forests or gardens, rainwater lingers in the cooler, looser soil. In city centers? It might vanish before doing much good. So supplementing that rain with well-timed watering ensures that water actually gets where it’s needed—deep underground.
It’s Not Just Survival—It’s Long-Term Strategy
Poznań’s approach to urban greenery isn’t reactive. It’s strategic. The focus isn’t just on keeping plants alive during hot summers but helping them grow strong enough to handle future droughts, wind, and wear.
That’s why the city’s green infrastructure investments prioritize:
- Deep-root watering during and after rainfall
- Automatic irrigation systems with sensors
- Long-term tree care plans for urban plantings
- Special attention to young trees in harsh locations
It’s all part of building a resilient city—where greenery isn’t decorative, but functional. Trees cool the streets, clean the air, and make urban life better. And they need a little help to do it.
Next Time It Rains, Don’t Be Surprised
So the next time you spot a Poznań watering truck during a rainstorm, don’t shake your head. Smile instead. Because now you know: watering trees in rain isn’t a mistake. It’s a clever solution to a complex urban problem. In a city where every drop counts, that little extra effort can mean the difference between surviving and thriving.
