The most common image for the labors of the month for September is the grape harvest in warmer climates and sowing seed and/or plowing in cooler climates. September is also a month that in cooler grain-growing climates might be the time to finish or start serious grain-threshing in areas where August is still too wet for threshing, or the harvest is later.
The anonymous Middle English lyric describing the labors of the months for September has:
With my flayll I erne my brede;
The flail of course is the tool used to beat or thresh the dry stalks of wheat, rye, oats or barley to loosen the grain. With threshing of course, comes winnowing, the process of removing the dried inedible chaff from the edible grain. In September the fields where summer legumes have been harvested are then ploughed for winter crops. Sowing is sometimes simultaneously shown with ploughing, especially in areas where winter wheat or rye are planted where the legumes have been harvested.
Threshing is a fairly common labor in cooler climates; picking grapes or the other stages of wine making is more typical in warmer climates. The most common images for the labors of September show people picking grapes, transporting picked grapes, or treading the grapes to express the juice for wine-making. Often grape-treading is depicted as a man in a large wooden barrel treading the grapes, with a cup of wine in hand. Sometimes people are showing bringing more grapes, or adding grapes to the barrel.
September from the Très Riches Heures de Duc de Berry