Tulasi Habba or Tulasi puja is observed on Ksheerabdi Dwadashi, which falls during Kartika masam. Tulasi Habba 2012 date is November 25. In some places, Tulasi Puja is also observed on Uthwana Ekadashi or Kartika Pournami.
As per Hindu scriptures and Puranas, Uthwana Dwadashi is the day during which Maha Vishnu awakes from his cosmic sleep. Lord Vishnu continues his Cosmic sleep for four holy months. During this period, Chaturmas Vrata is observed. Chaturmasya vrata starts on Ashada Shukla Ekadashi (Shayana Ekadashi) and ends on Uthwana Ekadasi.
Uthwana Dwadashi marks the Chaturmas vrata samapthi. On this day, devotees break their Ekadashi fast and observe Vishnu Puja. Tulasi Puja or Habba marks the marriage of Lord Vishnu and Goddess Tulasi. During Ksheer Sagar manthan, Tulasi plant was evolved from the Ocean of Milk and married to Lord Vishnu. Since then, on this day Tulasi – Vishnu vivaha is observed.
Tulasi Vivaha is also called as Tulasi Damodara Vivaha or Tulasi Salagrama Vivaha. Uthwana Dwadashi also signifies the beginning of Ksheer sagar mathan (churning of the milky Ocean).
Uthwana Dwadashi is also known as Ksheerabdi Dwadasi, Chilku Dwadasi, Yogishwari Dwadashi or Yogini Dwadasi in other places of India.