Crop rotation is an essential basis of an organic farming system. An activity theoretical
concept of object shall be used in examining planning processes of crop rotations. Farmers'
object construction means their creating and maintaining the social meaning and purpose of
the material farming activity. I shall assume the farmers´ object construction in planning crop
rotations to reflect their overall object in organic vegetable farming. First, this paper examines
theoretically the object in organic vegetable farming by devising a framework of different
types of object constructions. Second, two farms with organic vegetable production will be
described, and the farmers´ objects will be shown in the light of the histories of the farms.
This will show that the different types of objects have not evolved at random. Third, the
dynamic movement of the object construction in the crop rotation planning processes is
explored. The results will show that the farmers´ object, although historically understood, is
not fixed. On the contrary, the object is in a constant move and even contradictory
