The provisions of Sections 2-20-1 and 2-20-2 shall apply only when corn, oats, rye, wheat, barley or cotton seed hulls are sold in sacks, bags or other packages and shall not prevent the sale of any of said articles in bulk. The provisions of Sections 2-20-1 and 2-20-2 shall not apply to sales of grains or cereals by the producer or grower of such grains or cereals.