This is really interesting and detailed information. Many thanks! I really do appreciate your input. A few more questions:
1) Was Pennsylvania much more like New York then? Or were Pennsylvania and New York very different beasts economically and socially? How did Philadelphia and New York City compare?
2) Did Maryland move away from Virginia post-1750, as it became more industrial? Did this make it more like Pennsylvania?
3) How come the soils got exhausted in Maryland and not in Virginia?
1. New York, New Jersey and Pennsylvania were similar in that they relied mostly on the production and export of grains. New York was really only settled along the Hudson River south of Albany by 1770, with a few smaller scattered settlements outside of that area. Even Dutchess County was only opened up to settlement in the 1750s. However, this region produced over 1/3 of the wheat in British North America by 1770. As for New York City itself, its growth was largely the product of the Erie Canal in 1820, connecting it with the inland areas of the west, and giving it an advantage that neither Philadelphia, nor Baltimore had.
2. To call Maryland industrial anytime before 1840 is a stretch. The shipbuilding really seems to have taken off after 1790. However, heavy industry was still a long way way. After the decline of tobacco during the revolution (loss of markets), and the depletion of soils, Maryland along with Virginia began to farm grains along the coast (wheat, maize, rye, oats), as these were booming commodities. This coincided with the beginning of Europe's population growth, and a demand for grain and flour. Baltimore became a leading grain exporting port along the Chesapeake. Along with the need for interstate trade by sea, this allowed it to become the third largest city in the United States.
On a side-note, Richmond was mentioned, by 1830 Richmond rivaled Rochester, NY as the nation's leading flour milling city, allowing it to grow as a city.
3. The soils in Virginia around the Chesapeake Bay area were just as depleted. Tobacco depletes nitrogen and potash from the soil. Usually most land in the region yielded tobacco for 3-4 years. Afterwards, maize was planted, however this was conducive to erosion leading land to be abandoned. The abundance of land in 1750 led many poorer farmers to settle west. As late as 1760, the vast majority of inhabitants lived along the coast and there were still large areas of land available for settlement in Virginia and Maryland further west. With the British victory in the French-Indian War, this removed the largest obstacle to Westward settlement. Poor whites were among the first to move to present-day West Virginia, Kentucky, Ohio, Tennessee, and later further west.
What does all of the above mean. Firstly, the growing of grain was not as labour intensive as tobacco, meaning there were too many slaves in Virginia and Maryland by 1790. Some slave owners were no longer able to afford to keep them, and set them free. By 1810 23% of blacks in Maryland and 76% in Delaware were free (compared with 7% and 31% in 1790).
However, beginning in the 1790s, the invention of the cotton gin, coupled with Britain's industrial revolution allowed for cotton to boom in the deep South. First cultivated in large quantities in South Carolina and Georgia, it became the nation's leading export in 1803 (and would remain so until 1937). With the opening of new lands to settlement in Alabama and Mississippi, these would become the leading cotton growing states. Finally, additional cotton growing land was acquired with the Louisiana Purchase and the Mexican War. This allowed over 900,000 slaves from Virginia would be exported to other states by 1860 (this was their leading export). During the 1790-1800 some 40-50,000 were exported from Virginia and Maryland. The closing of the US to the international slave trade in 1808, proved to be a windfall for some slave owners in Virginia and Maryland.
Also, there were lesser numbers of slaves that would be exported to new tobacco growing areas in North Carolina and Kentucky. One has to remember that in 1772 North Carolina only exported 2% of the amount of tobacco that Virginia did and 5% the amount that Maryland did.