Why is my cabbage not forming a head?

Cabbage head formation requires sustained cool temperatures (15–22°C) for 4–6 weeks — missing this window in India's short cool season means the plant stays leafy. Transplant October–November in North India, not December onwards. Ensure nitrogen feeding until the plant has 12+ leaves, then switch to potassium. Container must be 12+ litres — undersized pots produce stunted, headless plants. Varieties matter: Golden Acre heads faster (60 days) than larger types.