The zodiac sign most often associated with the month of July in books of hours was Leo, represented by the lion. The most common labor for the month of July in terms of books of hours is the wheat harvest, seen in the image above in the field on the left, or sometimes, the last of the haying. If you look at this collection of July images from the Koninklijke Bibliotheek you can see images showing reaping, haying, weeding, and err, sleeping. Weeding was important because crops like beans or other legumes required constant attention to remove dock or other weeds that would compete with the actual crop for nutrients. Sheep shearing was possible too, as in the image above.
The anonymous Middle English lyric listing the labors of the months describes the labor of July as mowing:
With my sythe my mede I mawe
What’s probably meant by mawe (mow in Modern English) is harvesting the wheat. In many parts of Europe, wheat could be harvested twice a year, once in summer, and once in fall (the so-called “winter wheat,” or sometimes an alternative grain like rye, barley, oats, or millet). A double harvest relied on a system of rotating crops between three fields.
Harvesting wheat means first, mowing the stalks, usually with a scythe. Then, the stalks are bundled into sheaves, and brought indoors before being threshed, that is beaten so that the ripe grain falls off the stalk. Threshing usually took place in the cooler weather of late fall or early winter, under a roof (sometimes inside a special “threshing barn”). Winnowing, the process of separating the edible grain from the straw or chaff, is the next stage.