Amvuvācī is a popular vrata. In Devibhāgavatapurāṇa it is said that on the days of Amvuvācī the earth should not be digged up, and no washing with water should be done. Those who will dig up the earth, will incur the sin of brahmahatyā–

amvuvācyāṃ bhūkhananaṃ jalaśucādikañca ye
kurvanti bhārate varṣe brahmahatyāṃ labhanti te.

Generally in Bengal, Amvuvācī starts from the 7th day of Āṣāḍḥa, in Orissa, from the last day of Jyaiṣṭha, and continues for 3-4  days. It is difficult to describe how hard and painful a life the Bengali-Hindu widows had to live in this time, in the name of performing the vrata.

It is a matter of surprise that the composers of Smṛti-śāstra , who give dictums for the vrata and fasting, even they have not given any such dictum for the widowed women. But it was a must-performing vrata for the Hindu widows in Bengal. Some person with some ill intention inserted a popular śloka in the panjikā, where it was said that– yati(s) (disciplined persons), those who perform vrata, widows and brāhmaṇa(s) would not take cooked food. Whether in their own house, or in the house of some other people, they would not take any cooked food. If they do, that would be considered as the food given by a Chaṇḍāla–
yatino vratinaścaiva vidhavā ca dvijastathā
amvuvācīdine caiva pākaṃ kṛtvā na bhakṣayet.
svapākaṃ parapākaṃ vā amvuvācī dine tathā.
bhojanaṃ naiva kartavyaṃ chaṇḍālannamayaṃ dhruvam.

There is no proper origin or valid basis of this śloka. But on the basis of this śloka, brāhmaṇa(s) gave their verdict, the the poor widows became the worst sufferers.

For the three days of Amvuvāci, the widows neither cook, nor put fire in the oven, nor do they eat cooked food. Many among the widows continue these days by taking bread or fried bread or puffed, dry rice prepared before Amvuvācī. Many others do not take food for the whole day, and eat fruits at night. In such hardship, the widows had to spend the days of Amvuvācī in Bengal.

Since Amvuvācī falls on the days of the beginning of the monsoon, the farmers were asked not to till the land. So it was the holiday-time for them. It is believed that the mother earth menstruates in this time. The fair of Kāmarūpa and Kāmākhyā and the Raja festival of Orissa coincide with this. The scholar Chintaharan Chakraborty has said, in the ancient Smṛti-texts, there is only the custom of not tilling the land– and that is a verdict for the farmers. There is no connection of the brāhmaṇa(s) or widows with this.

He has written that the renowned composer of Smṛti-texts in Bengal, namely, Vṛhaspati Rāyamukuṭa, Śrīnātha Ācārya Cūḍāmaṇi,, Govindānanda Kavi-kankanārya, Raghunandana and Gadādhara of Orissa– all of the, citing ancient pramāṇa, said that on the day of Amvuvācī, any kind of tilling the land, sowing seeds or digging the soil is forbidden. All agricultural acts are forbidden. There is evidence of this in Smṛti Ratnahāra by Vṛhaspati Rāyamukuṭa. He says– one should not till the land or sow seeds in the land during this time–

tatrakarṣaṇavījavapanādikaṃ na kāryam.

Śrīnatha Ācārya Cūḍāmaṇi has written–

tatra bhūkarṣaṇavīja vījavapanādi na kartavyam.

etaddinatrayaṃ yāvad vedo̍pinādhyeyaḥ..

mṛgarkṣe̍rke nidāghasya tanmadhye̍pi dinatrayam
rajasvalā syat pṛthivī kṛṣikarmavigarhitā.

Such an opinion is still at work that during this time the earth goddess is on her menstruating phase. In Kāmākhyā, too, Mahādevī is identified with the earth goddess and she is also believed to be menstruating. This belief was evident before the Bengali Smṛti-scholar Raghunandana. Govindānanda, a scholar who preceded Raghunandana has written, contesting this view– modern scholars say that at this time the earth becomes impure. But this can never be possible. If the the earth becomes ̍impure̍, there will be complete fasting all over the world. But it does not occur–

bhūmeraśuddhi kutaḥ. anyathā bhojanaṃ devārcana-pañcaṃahāyajñā dīnāmapi niṣedha prasangaḥ.