2012
Saturday, 24 November 2012
In 2012 the tithi runs from 10:38 am on 24 Nov to 12:38 pm on 25 Nov; it is running at pradosh, the twilight just after sunset on Saturday, 24 November 2012, so that is the day of Tulsi Vivah.
2013
Thursday, 14 November 2013
In 2013 the tithi runs from 7:11 pm on 13 Nov to 6:55 pm on 14 Nov; it is running at pradosh, the twilight just after sunset on Thursday, 14 November 2013, so that is the day of Tulsi Vivah.
How the date is fixed
Tulsi Vivah falls on the twelfth day of the bright half of the lunar month Kartika (Shukla Dwadashi). The date is the day on which that tithi is running at pradosh, the twilight just after sunset.
About
Tulsi Vivah is kept on the twelfth tithi of the bright half of Kartika, the day after Devutthana Ekadashi, in November; some households perform it on the Ekadashi itself or on any day up to Kartika Purnima. The ceremony is held at dusk, so the day whose pradosh carries Dwadashi is chosen. Tulsi is married to a shaligram stone or an image of Vishnu with the full wedding rites. The day marks the opening of the wedding season after chaturmasa.
How it is observed
A mandap is set around the tulsi plant at dusk and the wedding rites performed, followed by a feast.