Tucked away in the Book of Common Prayer Calendar on August 1st you will find Lammas Day.  This is said to go back to the Anglo Saxon practice of offering loaves of new corn on this day at a special Mass – hence Lammas or Loaf Mass derived from the Anglo-Saxon Hlafmaesse.  So Lammas Day was a kind of Harvest Thanksgiving related to the beginning of the Harvest rather than its end.  The ceremony did not survive the Reformation but has been revived in more recent times in some places.  You will find Common Worship provision here. (1)(2)

The loaves of bread in the shape of a sheaf of wheat, which some bakers produce and which sometimes form part of our modern Harvest Festival church decorations, may originate from the bread which used to be brought to churches on Lammas Day. (3)

According to various customs, of very ancient origin, certain lands used by their owners for growing wheat and other crops, were thrown open for common pasture on a particular date.  This date was usually Lammas, August 1st, also known as the day of St Peter in Fetters (St Peter in Chains).  The lands remained open until spring of the following year. (4)

References

1. Sparrow Simpson, W.J. (1901) The Minor Festivals of the Anglican Calendar, London: Rivingtons.

2. © Archbishops' Council of the Church of England (2006) Seasons and Festivals of the Agricultural Year.  Available from: http://www.churchofengland.org/media/41161/tsagyear.pdf (Accessed 26 June 2013) (Internet).

3. Hole, C. (1941) English custom and usage, London: B.T. Batsford Ltd.

4. Wright, A.R. (ed Lones, T.E.) (1940) British Calendar Customs, England, Vol III: Fixed Festivals, London: William Glaisher Ltd.