Matsyapurana 16.58

16.58

kanyākumbhavṛṣasthe 'rke kṛṣṇapakṣeṣu sarvadā
yatra yatra pradātavyaṃ sapiṇḍīkaraṇāt param
tatrānena vidhānena deyam agnimatā sadā //

In this way, an Agnihotri should perform Śrâddha in the dark fortnights of the months when the sun is in the sign of Virgo, Aquarius, and Taurus. Whenever the Sapiṇḍi karaṇa Śrâddha is to be performed, there also the above ceremonial should be observed by one who keeps the sacred fire.—58.