When does school start in the fall by state?

Back in the old days, most of North Americans and Europeans worked in agriculture. At the harvest period, (usually in summer, depending on the type of crop) the work required extra sets of hands to for the labor. Since big machinery weren't there to facilitate the work, children of the family were expected to help in the fields. It would be logic to think that once public school was open to kids of all social levels it would have to start in fall to allow the children in agriculture to begin their studies at the same time.