Brassicas
Red cabbage
Brassica oleracea var. capitata f. rubra
Timings for your region
Suggested: Moderate · Explained in the glossary
Start indoorsearly March – mid April
Plantingearly May – early June
Harvestmid August – early November
Practical tip
Treat like white cabbage, but allow a little longer. The heads keep for months in a cool cellar.
Origin & history
Red cabbage is the same species as white cabbage, just a colour form: anthocyanins in the leaves give it the violet. These pigments react to acidity — cooked with apple or vinegar it turns red, in hard limey water it goes bluish, and the double German name (Rotkohl in the north, Blaukraut in the south) is usually traced back to exactly that. It has been described in European sources since the late Middle Ages and was long a purely winter vegetable.
Varieties
Early varieties give smaller heads for summer use; true storage varieties such as “Marner Lagerrot” need until October and become firm and heavy in return. For the cellar always take a storage variety — an early head is loosely built and rots from the inside in store. F1 varieties are more uniform and split less often; open-pollinated ones you can save and re-sow yourself.
Care
The 50 cm spacing is meant literally: planted tight, red cabbage barely forms a head and stays as a loose rosette of leaves. What decides the crop is water in August and September while the head is filling — in dry weeks soak it thoroughly twice a week rather than dampening it daily. Earthing up steadies the heavy heads, and from September stop feeding nitrogen, because softly grown heads do badly in store.
What can go wrong
Small, loose heads are the commonest frustration and almost always have one of two causes: too little room or drought during head formation. Planted too late it comes to nothing either — red cabbage needs its full run of weeks, and a July planting will not head up. Against the cabbage root fly at the root collar a collar or netting from planting day helps; against clubroot only the four-year break does.
Harvest, storage & kitchen
Leave it standing as long as you can; light night frosts do the head no harm. Cooking calls for acid — a grated apple, a splash of vinegar or red wine keeps the colour red; without it the cabbage turns grey-blue. Shredded very finely and kneaded with a little salt it makes a crisp raw salad, and blanched and frozen in portions you still have it once the stored stock is gone.
All timings are guide values for the given climate, not a guarantee. Weather, aspect and variety all have a say.