This is truly amazing – imagine growing citrus beneath a snow drift!
Citrus fruits (oranges, lemons, mandarins, tangerines, grapefruits, limes, pomeloes) are the highest-value fruit crop in terms of international trade. Citrus plants are not frost-hardy and can only be grown in tropical and subtropical climates – unless they are cultivated in fossil fuel heated glasshouses.
However, during the first half of the twentieth century, citrus fruits came to be grown a good distance from the (sub)tropical regions they usually thrive in. The Russians managed to grow citrus outdoors, where temperatures drop as low as minus 30 degrees Celsius, and without the use of glass or fossil fuels.
By 1950, the Soviet Union boasted 30,000 hectares of citrus plantations, producing 200,000 tonnes of fruits per year.
The Expansion of Citrus Production in the Soviet Union
Before the first World War, the total area occupied by citrus plantations in the Russian Empire was estimated at a mere 160 hectares, located almost entirely in the coastal area of Western Georgia. This region enjoys a relatively mild winter climate because of its proximity to the Black Sea and the Caucasus Mountain range – which protects it against cold winter winds coming from the Russian plains and Western Siberia.
Nevertheless, such a climate is far from ideal for citrus production: although the average winter temperature is above zero, thermal minima may drop to between -8 to -12 degrees Celsius. Frost is deadly to citrus plants, even a short blast. For example, at the end of the 19th century, the extensive citrus industry in Florida (US) was almost completely destroyed when temperatures dropped briefly to between -3 and -8 degrees Celsius…
(Read the rest at Low Tech Magazine – it’s utterly fascinating!)