Research about this topic:
What is urban gardening?
Urban gardening came from the USA to Europe and got big in the '90s. The focus is on beautifying and enriching life in the city and creating new communities. It has many different types of urban gardening. These different types you can find in the first link.
The motto of urban gardening is recycling instead of high-tech, creativity instead of professionalism.
Urban Gardening and Urban Farming have existed since the construction of urban developments. The lack of transport facilities and the short shelf life of food made it impossible to produce it in regions far away from the demand for this food. With increasing globalization and improved transport routes, the knowledge of how to grow vegetables and fruit was then lost again.
Nowadays, a large part of the urban population is again interested in producing their own vegetables and fruit.
In Switzerland, we have many shops where you can buy things for urban gardening. For example in the second link there you can find a shop in Wädenswil, Switzerland.
Link 1 - what is urban gardening (reset.org)
Link 2 - urban gardening shop
Link 3 - urban gardening information
This is a balcony from Oerlikon, Zürich where the resident does urban gardening.
For this research, I took 30min of my time.