Kartik Vrat Udyapan (Karthika Masa Vratha Udyapanam) is observed on Kartik Purnima (Karthika Pournami). In 2018, Kartik Vrat Udyapan date is November 22.
The pujas, all other rituals, rules and code during the month are called as Kartika Masa Vratam. There are certain rules and codes to perform Kartika Masa vrata. The Karthika Purana details the rituals and customs to be performed during the month of Karthik.
In 2018, Kartik Month begins on November 8 and ends on December 7 as per Gujarati, Marathi, Kannada & Telugu & Goa calendars. In 2018, Kartik Month begins on October 25 and ends on November 23 as per North Indian Hindi Calendar.
Here is the detailed vidhi of Kartik Vrat Udyapan (How to conclude Kartik Maas Vrat)..