The heat this summer never ends.

Big cities like Frankfurt in particular notice this, as residents suffer particularly badly from the effects of climate change.

Ideas that help make the city cooler are all the more in demand.

The two Frankfurt product designers Nicola Stattmann and Carlotta Ludig have been working on such solutions with their "Office for Micro Climate Cultivation" for two years and this year they made it into the final round for the Frankfurt Founders' Prize, which will be awarded in September.

The two women are experimenting with fast-growing annual and perennial climbing plants.

Because trees root too deep and too wide.

Their ideas include mobile shadow walls, up to ten meters high, only 2.50 meters wide and deep.

Well-known plants such as bell vine, morning glory, runner beans and hops grow in it, as well as lesser-known plants such as Indian spinach or a cheese plant that smells of Camembert.

What they all have in common is that they twine in no time and form dense greens.

After many trials, 38 types of plants were found that are perfectly suited for improving the city climate.

Green oases for the cities

The first two test plants of this type can be seen in Witzenhausen in northern Hesse on a 350 square meter test plant of the Institute for Organic Agricultural Sciences at the University of Kassel and south of Ulm on the site of a well-known nursery in Illertissen.

The systems are not public because the two developers want to patent their idea.

The examination by lawyers is ongoing.

So much can be revealed: Nets made of flax rope are pulled up on steel rods, comparable to scaffolding, like sails on a boat, on which the climbing plants climb and can be aligned according to the direction of the sky and wind.

Thanks to various platforms, the plant pots, which are only 30 by 30 centimeters in size, can also be placed at different heights, so that the greening only begins at a height of three meters.

This creates a kind of plant tunnel under which city dwellers can continue to walk or ride their bikes.

"It's a modular system that can be used to shade cycle paths and design entire avenues," explains Nicola Stattmann.

The fifty-two-year-old also teaches students in various project professorships in product design and founded her own furniture company together with her brother 20 years ago, which takes up the tradition of the 120-year-old family carpentry shop.

Stattmann is interested in the environmental and climate aspects of the project as well as in design aspects.

"We're creating something completely new that will suit baroque Vienna just as much as it does Tokyo or the financial district of Frankfurt."

Negotiations with various departments of the city of Frankfurt are ongoing.

The start-up company wants to go into series production with its shading idea in as little as two years.

"We need series and mass, an affordable ecological solution"

The advantage: In contrast to facade greening, which is anchored in the building, the green sails can be set up anywhere in the city, according to the idea of ​​the founders, even where there are no houses and glowing asphalt heats up the city.

Different studies show that it can be between 1.5 and 8 degrees cooler in the city with greenery.

Because while heated concrete surfaces also radiate heat at night, the moisture in the leafy green evaporates and cools down.

The plant systems are watered automatically with pipes that deliver water precisely and only drop by drop.

In the fall, the biomass is harvested and composted together with the ropes, which in turn is intended to generate energy.

"We need series and mass, an affordable ecological solution," says Stattmann.

Only individually green houses are not enough.

In any case, not only is the green thriving in the test facilities, insects threatened with extinction are also humming there.

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