Red cabbage

You grow red cabbage as an annual vegetable and harvest it before continuous frost. You may well allow light frosts, which make it sweeter, but it does not overwinter in the bed, because the heads split in hard frost. Pull the heads out of the ground with the stalk, remove loose outer leaves and store them cool, dark and well ventilated in the cellar, hung head-down by the stalk or on a slatted rack; then late varieties keep into late winter.

You propagate red cabbage exclusively from seed. Start early varieties from the end of February/early March in seed pots on the windowsill or in the greenhouse (germination temperature 16 to 20 °C), mid-early varieties following from mid-March, late varieties from mid-April to early May. Place the seeds about 1 to 2 cm deep in seed compost; they germinate after around a week. After 4 to 6 weeks, when the seedlings are strong enough, harden them off and plant them outdoors (planting distance 40 to 50 cm for early varieties, rather 60 to 70 cm for late ones). Set the young plants deep, up to the seed leaves, so that they form additional supporting roots. Direct sowing outdoors is possible from mid-April, once the soil has warmed to at least 10 °C; if there is a risk of late frost, cover the rows with horticultural fleece. If you want to save your own seed, note: red cabbage is biennial and flowers and sets seed only in the second year, after it has had a cold stimulus over winter. So you overwinter strong, healthy plants and, in spring, carefully cut into the top layers of leaves so that the flower stalk can push through the firm head. True-to-type offspring only works with open-pollinated varieties; hybrid varieties (marked “F1”) are not suitable for this.