So why does the season matter, you ask? Because we often plant cool-weather crops (like carrots, cabbage, and mustards) in spring, but truth is, these crops are better off planted in fall when they can mature in cold weather.
The standard practice of planting them early in the season and letting them mature in warm weather actually stops their natural physiological response to cold stress—and it’s not necessarily a good thing.
You see, all these root vegetables, brassicas, and other leafy greens want to develop in cold weather. They are well adapted with a defense mechanism that not only keeps them from dying in winter, it makes them sweet and delicious.
When temperatures drop, root crops convert some of their starches into sugars. This keeps the water in their cells from freezing, and it works the same way as putting salt on a road to keep it from icing over.
A lower freezing point means that while the cells inside the plant might have icy cold water, that water won’t turn into ice. Think of it as nature’s antifreeze.