Tulsi vivah puja is observed either on Kartik Ekadasi or Ksheerabdi Dwadashi or on Kartik Purnima day. Tulsi Vivah Vrat katha or the story of Tulasi Vivaha vratham is associated with the legend of King Jalandhar and his wife Jalandhar.
The story explains the great devotion of Vrinda towards her husband and Lord Vishnu. Vrinda (Tulsi in her previous birth), a devotee of Lord Sri Maha Vishnu, was married to the demon King Jalandhar. She worshipped Vishnu to protect her demon husband from akaal mrithyu (untimely death).
Jalandhar misused the blessings of the Lord and harassed saints, sages and created havoc in the world. To protect the world from the demon, Lord Maha Vishnu took the form of Jalandhar and stayed with Vrinda.
After the death of Jalandhar, Vrinda came to know the truth and cursed Lord Vishnu and turned him into a stone known as ‘Shaligram’. Then, she emerged as Tulsi plant. This is the reason why Vishnu Puja will not be completed without the leaves of Tulsi plant. Lord Vishnu gave Vrinda a boon that his abode will be known as Vrindavan (Brundavanam) on her name.
Tulsi puja is performed by married women for wellbeing of their husbands and for marital bliss. Unmarried girls perform Tulsi pooja to get good husbands. Tulsi Vivah puja 2018 dates are – 19 November, 20 November, 22 November or 23 November.