It is a common practice to offer 'tarpanam' to our ancestors on this day, to honour them and to receive their eternal blessings.
Even though tarpanam to ancestors should be performed during the new moon every month, yet the tarpanam ritual on aadi ammavasai is considered to be very special as it is believed that our forefathers pay us a visit on this day.
Aadi Ammavasai Fasting
Among the common ritual for this day is to observe fasting. However, not everyone is allowed to do so. Only widows and son with deceased parents are allowed to fast and perform the ritual. Sumangalis (married ladies) are forbidden from fasting and conducting the rituals.On this day, it is auspicious to visit temples which are located along the river banks, next to the sea or any Shivan Temples to perform tharpanam. But if you're unable to visit the temple to perform the rituals, you can also opt to perform tharpanam at your home instead.
These are the rituals that should be followed on Aadi Ammavasai: