Is it permissible to pay Zakat al-Fitr with vegetables or potatoes, knowing that potatoes are a staple food, and what is the equivalent measure of a sa‘ thereof?

The obligatory amount for Zakat al-Fitr is one Sa' of food, which is the staple food that can be stored, such as grains and dates. Giving potatoes or vegetables is not permissible because they are neither measured by volume (kayl) nor can they be stored. This is based on the Hadith of Ibn Umar (may Allah be pleased with them both): "The Messenger of Allah (peace be upon him) enjoined Zakat al-Fitr: one Sa' of dates, or one Sa' of barley." And the Hadith of Abu Sa'id al-Khudri (may Allah be pleased with him): "During the time of the Messenger of Allah (peace be upon him), we used to give one Sa' of food on the day of Fitr. And our food was barley, raisins, dried yogurt (aqit), and dates." What is measured by Sa' are grains. As for potatoes, they are not measured by volume. Bread is also not permissible because it falls outside the categories of items measured by volume and those that can be stored.