Kale tolerates cold weather so it can be started extra early. Start kale seeds indoors 3/1 at 72-85° (can use a heating mat). Days to germination: 5-8. Transplant outside 3/27, 12” apart. Or, sow kale seeds directly outside anytime 3/27 – 8/1. If sowing seeds outside, plant 3-4 seeds together in a group ¼ ” deep, spaced 10” between groups. Keep seeds evenly moist until germination. Thin to the strongest plant in each group. For baby kale, broadcast sow seeds 2-3” apart. Protect kale plants from deer, groundhogs, and rabbits which will devour them. Kale plants may be eaten by caterpillars. If they cause damage, hand remove caterpillars or spray organic BT.
Baby Leaves, for cut-and-come-again: when leaves are 3-4”, cut entire plant with scissors 1-2" above soil level so you don’t damage the growing crown. Plants will re-grow so you can return for many harvests. Mature Kale: harvest individual leaves off of mature plants once they are 2 months old. Don’t remove more than 1/3 of the leaves at one time.
Kale is somewhat difficult to save seed from. Kale plants must overwinter in order to bloom and produce seed. Sometimes kale plants will survive the winter with protection. Kale is in the Brassica family so it is insect pollinated and cross-pollinated. Kale will cross with any Brassica oleracea that are flowering at the same time (broccoli, collards, cabbage, brussels sprouts, kohlrabi, cauliflower). Isolation distance: ½ mile. It can suffer from inbreeding depression if you don’t save seeds from enough plants. Minimum population size: 10-50 plants. To harvest seed, allow plants to flower and collect seed.