I finally found out more about those clusters of micro gardens I saw in the Swiss countryside near Zurich. They are called “family gardens.”
In a nutshell: If you live in an apartment in a big city like Zurich you can rent a garden in one of Switzerland’s designated tracts of gardening land. The average plot is about 43 feet square and you can usually build a small house and a terrace on it. There is no electricity but most tenants bring in an outdoor grill, kerosene lantern, and/or a camping-type stove so they can enjoy the fruits of their labor right on the spot. One cool point to make note of – tenants are strongly encouraged to follow “near-to-nature” gardening methods aka organic gardening.