Today, we are often being told to eat local and seasonal food, either because other crops have been transported over long distances or because they are grown in energy-intensive greenhouses. But it wasn’t always this way. From the sixteenth to the twentieth century, urban farmers grew Mediterranean fruits and vegetables as far north as England and the Netherlands, using only renewable energy.

These crops were grown surrounded by massive ‘fruit walls,’ which stored the heat from the sun and released it at night, creating a microclimate that could increase the temperature by more than 10°C. Later, greenhouses built against the fruit walls further improved yields using solar energy alone.

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