September 29th, Wodan's Day

On September 29th, we celebrate the Germanic Wodanstag.

Thanksgiving festival for the entire harvest in honor of Wotan/Odin

It is part of the harvest custom that Wodan is invoked during the harvest and at the harvest festival "for good grain in the next year".

A small patch of the field is not mown for this purpose; the ears of grain are tied together and sprinkled with water. The reapers turn their scythes and whetstones towards the bundle of ears and call out to the god Wodan three times:

Wode, Wode,
Hale dinem Rosse nu Foder.
Du Distel un Dorn:
Tom andern Jahr beter Korn.

For Wodan's horse "Sleipnir," a wreath is bound from ears of grain with interwoven flowers; this wreath is watered by the wreath binders. During the water consecration, the god Wodan is also invoked. The words "Du Distel un Dorn ..." are the plea for a better harvest in the coming year. – Where thistles and thorns stood this year, abundant grain shall grow then. The wreath is handed over to the lord of the manor. Wodanstag is to be understood as a consecration and sacrificial festival, which we celebrate with holy pagan rituals and customs.

Following Wodanstag, the Thanksgiving festival is celebrated on September 30th; the festivities merge into one another.

Sources:
"Handbuch der Deutschen Mythologie" by Professor Dr. Karl Simrock, page 598, Verlag Adolf Marcus, Bonn, 1878 edition.
"Die deutschen Opfergebräuche bei Ackerbau und Viehzucht" by Dr. Ulrich Jahn, page 164, Verlag Koebner, 1884 edition