How does a cabbage head form?
Heading cabbage is a cultivar group of Brassica oleracea that develops tightly overlapping leaves. Green and red types are common. The edible head is not a fruit but a structure formed by leaves around a shortened stem.
Conditions for heading
Moderately cool weather, adequate light, and balanced water and nutrients support heading. Seedling stress, unsuitable season, or overcrowding can impair development. Early and late cultivars mature at different rates. Check drainage and organic matter before planting. Broccoli and cauliflower are other groups of the same species, not crops with identical harvest criteria.
Splitting and crop health
Leaving mature heads too long and sudden water uptake after drought can contribute to splitting. Harvest at suitable firmness. Watch for caterpillars and root diseases. Rotation away from related crops can reduce some disease pressure without solving every soil problem. Removing lower leaves indiscriminately reduces photosynthetic area and may restrict head development.