Kale and collards can both be grown as a cut and come again crop for salad mixes by direct-seeding and cutting baby leaves. They will re-grow if you pick leaves from the bottom up, as you need them. Continue harvesting lower leaves as they mature—plants will keep producing all season. Kale can overwinter in many areas. In fact, the leaves get sweeter after frost, though growth will slow. In spring, the surviving plants start to flower, so eat the delicious flowering steps and buds.