Early Jersey Wakefied Cabbage and Calabrese Broccoli plants are in the hardening off period. They need to be brought outside to acclimate them to the cool air, sun, and wind for about 10 days before planting in the garden. These cole crops can take a light frost but must be protected from a heavy frost. The cabbage plants are on the right and the broccoli on the left. Notice the difference in the leaves. Cabbage has a rounded leaf while Broccoli has an elongated slightly scalloped leaf.