Centeotl holds the fourth position among the Yohualteuctin, recurring every ninth day of the tonalpohualli starting from day four, a rotation that runs independently of the twenty day signs and the thirteen trecena numbers and realigns with them only once every 2340 days. A date under Centeotl's night was read, following the tonalpouhque's layered method that Sahagun describes, as adding the maize god's character of growth, sustenance and patient increase to whatever the day sign and trecena already indicated, a favourable colouring for undertakings tied to planting, provisioning, or the raising of children, though the surviving sources give no complete reading by reading manual and much of this inference follows from Centeotl's known character rather than a preserved liturgy for night lord readings specifically.
The night lord cycle's independence from the day sign cycle means Centeotl's dates fall under every one of the twenty signs and every trecena in turn across a full 2340 day period before the pattern repeats, so there was no single fixed maize day in the tonalpohualli; the calendar priests read Centeotl's turn wherever it fell, in the codices' tonalamatl tables that lay the nine lord row beneath the twenty day sign row for direct reference, work Duran also describes the priesthood performing to advise on the timing of both private and civic undertakings.
Sources Cycles of Time and Meaning in the Mexican Books of FateElizabeth Hill Boone with Florentine Codex: General History of the Things of New SpainBernardino de Sahagun; translated by Arthur J. O. Anderson and Charles E. Dibble, Book of the Gods and Rites and The Ancient CalendarDiego Duran; translated by Fernando Horcasitas and Doris Heyden