Many crops like cabbages, carrots, parsnips and swedes taste a lot better after a period of frost and this is because they are often much sweeter.
Plants take in carbon dioxide and water and through photosynthesis use the sunlight to convert it into sugar and starch – this is the energy of the plant.
A period of frost encourages some hardy plants to convert more starch into sugar and this then keeps the plants warm as they metabolize the sugar to create energy.
That’s why these plants taste better after cold weather as they contain a lot more sugar! Green cabbages like this can tolerate temperatures as low as -10 °C. No wonder we eat so many of them during the winter!