Sounds like the USSR's successful attempts to grow citrus fruits in cold climates, when imports were discouraged for political reasons immediately after the Rus

Sounds like the USSR's successful attempts to grow citrus fruits in cold climates, when imports were discouraged for political reasons immediately after the Russian Civil War. Necessity is the mother of invention: https://www.lowtechmagazine.com/2020/04/fruit-trenches-cultivating-subtropical-plants-in-freezing-temperatures.html https://www.lowtechmagazine.com/2020/04/fruit-trenches-culti...