Temperate oceanic climate, 30 miles from the Atlantic at 51N, low light levels. Average 55 frosts per winter of -1 to -8C (30-18F); these leaf-producing plants survive most winters, when sown early autumn as in the video.
The parsnips (sown March) survive much frost and improve in flavour, see how they prosper in no dig soil.
Harvestable amounts are low in winter, because of coolness and lack of light.
Then a bonus is the strong growth in early spring and welcome harvests during the hungry gap, especially of spinach.