Sarva Pitra Shradh is commemorated on the Amavasya (new moon) of Ashwin Krishna. If Shardh has been missed on that particular day or someone’s Shradh Tithi (date) is unknown, Shradh can be done on the same day. At evening, Poori (fried bread) and special dishes (Kheer, Halwa etc.) have been kept on the door.
It signifies that ancestors should not go hungry; iIn the same way lighting signifies brightening their way of ancestors. Ashwini Amawasya is also called as Pitra Visarjan.By feast and donating the brahmans, ancestors are being satisfied on this day. It is a belief that at the time of Visarjan ancestors blessed their sons.