Windows are local month/day spans and repeat every year; a window whose end falls before its start wraps New Year. During one, a giant of that crop grows in the yard and every harvest of it feeds the giant. Rows with an impossible date, an unknown crop, a blank id or a duplicate id are dropped by the game, and a calendar where nothing survives leaves players on the built-in seasons. Stored as config/events in Firestore — the game's code calls these events; everything you see calls them seasons.