Many religious traditions, as pointed out by George Megas, are rural, with ancient roots in the expectation of a good harvest.
Because even the weather conditions throughout Greece are not the same, the beginning of agricultural work, especially the seeding, does not take place at the same time, and so basically the same custom takes place on different days shortly between each other.
This explains the fact that the feast of the Entrance of the Theotokos (Nov. 21) seals the end or the middle of seeding. This is why the people call the Panagia either Aposporitissa (After the Seeding) or Mesosporitissa (Middle of the Seeding) and consider her the protectress of the harvest (the Greek word for "harvest" is σοδειάς, which sounds like εισόδια, the Greek word for "entrance"), hence also the association with the word Aposodeia (After the Harvest).
The day before or on the day of the Entrance, as well as that of Saint Andrew (Nov. 30), and the latest on that of Saint Barbara (Dec. 4), many housewives boil many seeds with: wheat, barley, rye, corn, beans, chickpeas and fava beans and they distribute them like kollyva to the neighborhood, for them "to seed". From this a plate is "brought" (εισάγουν) to church, where a prayer is read over it during the Liturgy and is distributed to the faithful. A portion is returned to the house. From this a portion is given to the animals, especially "plowing cattle" and "productive animals", and the rest is cast by the farmer in the field "to spread the seed". Elsewhere they take many seeds to the fountain either to feed them or to wash them. They throw the seeds in the water and say: "As the water runs, so may life." They then take water and return home. The offering of many seeds has the character of kollyva for the departed.
The Panagia, therefore, is associated with a good harvest (Καλοσοδειά), the fertility of the earth, which suggests the customary multiple seeding, that is, the offering throughout almost all of Greece of food that has been prepared together with many seeds and grains. The people call it πολυσπόρια (polysporia) or μπόλια (bolia), or μπομπόλια (bombolia), μπουσμπουρέλια (bousbourelia).
Extracted from a speech at the opening of the Museum of Bread in Amfikleia on November 21, 2003 by Katherine Polymerou-Kamilaki, Director of the Research Centre for Greek Folklore of the Academy of Athens.
Source: Translated by John Sanidopoulos.