For storage cabbage, start seeds in containers June 1st. Days to germination: 5-8. Transplant outside 7/1, 18-24” apart. Or, sow cabbage seeds directly outside anytime 5/1 – 7/1. If sowing seeds outside, plant 3-4 seeds together in a group ¼ ” deep, spaced 18-24” between groups. Keep seeds evenly moist until germination. Thin to the strongest plant in each group. Protect seedlings from slugs and cabbage plants from deer, groundhogs, and rabbits. Cabbage plants may be eaten by several different species of caterpillars. If they cause damage, hand remove caterpillars or spray organic BT. Plants are hardy and may survive winter outside.
Cabbage is ready when the head feels firm when squeezed. To harvest, cut heads on underside. Dottenfelder preserves for months at 33°F, with high humidity and good air circulation.
Cabbage is difficult to save seed from, so research further before attempting. Cabbage plants are biennial so they will need to be dug up in the fall, stored over winter, & replanted in spring. Cabbage is insect pollinated & will cross with other Brassica oleracea especially flowering broccoli & cauliflower. Isolation distance: ½ mile. Minimum population size: 20-50 plants.