2021
Monday, 15 November 2021
In 2021 the tithi runs from 6:39 am on 15 Nov to 8:02 am on 16 Nov; it is running at pradosh, the twilight just after sunset on Monday, 15 November 2021, so that is the day of Tulsi Vivah.
2022
Friday, 4 November 2022
In 2022 the tithi runs from 6:08 pm on 4 Nov to 5:07 pm on 5 Nov, and it never reaches pradosh, the twilight just after sunset, so the day on which it begins is taken: Friday, 4 November 2022.
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.