Dwidala Vrat is part of the Chaturmasa Vrata and is the last phase of the four-month Chatur Mas Vrat. Dvidala Vrata begins on the Dwadashi day in Shukla Paksha (12th day during waxing phase of moon) of Ashwin month and ends with Kartik Shukla Ekadasi. In 2016, Dwidala Vrat begins on October 13 and ends on November 10. Dvidala Vrata is also known as Bahubeeja Vrat.
Dwidala here implies those grams, lentils and seeds that break into two equal parts. Such lentils and grams are avoided during the period. Those lentils that are avoided are black gram, green gram, bengal gram, masoor al, horse gram, red gram, etc,.
Some people also avoid green leaves during the period and those plants that produce vegetables with numerous seeds.
Dwidala Vrat is only observed by some Hindu communities.