It is common knowledge that kale should only be harvested after the first frost. But is that really true? And what happens if he gets several frosts? Here's everything you need to know about kale and frost.

After frosting, kale contains less starch and more sugar

Does kale need frost to taste delicious?

jain There is a widespread opinion that kale would convert starch and thus bitter substances into sugar when it freezes. It is not so. However, the cold - even at low temperatures above 0°C - leads to changes in the metabolic processes: These are shut down and the kale thus forms less and less starch. At the same time, however, photosynthesis continues, leading to the formation of glucose. This means that kale forms more sugar than starch in frost or low temperatures, which leads to a reduction in bitter substances and an increase in sweetness.

Harvest kale after the first frost?

Kale is harvested from October to December, often as late as January or February. From this it can be deduced that kale can also be harvested if it has suffered more than one frost. If you only ever harvest the outer leaves, it will continue to grow and you can continue to harvest. However, as I said, the metabolic processes are slowed down when it is cold, so that the plant also grows more slowly and eventually stops growing altogether.

simulate frost

You read again and again that you can simply put bitter cabbage in the freezer and simulate the sub-zero temperatures so that the starch turns into sugar. Unfortunately, this magic trick doesn't work because, as explained above, it's not a conversion of starch to sugar, it's a change in metabolic processes, and that only happens in living plants.

The exception: the Italian variety Nero di Toscana

The Italian kale variety Nero di Toscana is an exception in terms of harvest time. This variety is also called black cabbage (Italian "nero" = black) because of its blue-green color. Like the other types of kale, it is also harvested from October to December, but this kale also tastes good before it has felt frost or severe cold. Its taste is slightly reminiscent of broccoli. More information about the different types of kale can be found here.

tips

Kale can freeze too! Pay attention to the frost hardiness that is written on the seed packet. Here you can find out the frost hardiness of some types of kale.

Category:

Vegetable garden