Shatapatha Brahmana 4.6.8.11

4.6.8.11

atha yadahareṣāṃ krayo bhavati | tadahargārhapatyāṃ citimupadadhātyathetarebhya upavasathe dhiṣṇyānvaisarjinānāṃ kāle prācyaḥ patnya upasamāyanti prajahatyetamaparamagniṃ huta eva vaisarjine

Then, on whatever day their purchase (of Soma-plants) takes place, on that day he piles up the Gârhapatya hearth, and on the Upavasatha day the dhishnya hearths for the others. At the time of the Vaisargina offerings the wives come forward together; they (the sacrificers) abandon that (common Gârhapatya) fire. As soon as the Vaisargina offering has taken place,--