Only when it gets uncomfortably cold outside, only when frost comes over the plant, does kale achieve its full flavour. Unlike cauliflower and white cabbage, kale needs severe frosts to develop its full flavour. Only the cold increases the sugar content in the leaves of kale. Therefore you have to wait until after the first frosty nights to harvest it. The softening cell structure is a further effect of the cold on kale. This makes it easier to digest.
When harvesting, the young leaves should always be cut from the centre as these are the most tender and therefore taste best. Of course, if large quantities are required, you can also cut off the complete plant above ground. However, it should be ensured that yellow and oversized leaves are not used for cooking. These must first be carefully plucked off.
If the stalks are left standing after harvesting the leaves, the small shoot can still be cut next spring as a tender cabbage sprout. However, if the kale begins to flower, pull the plant out of the soil and throw it on the compost.