What a Plow Does
A plow prepares soil for planting by cutting it open, loosening it and, in many designs, turning it over. Turning the soil buries weeds and old crop residue and brings fresh soil to the surface. Different soils and climates call for different tools, and the history of the plow is largely the story of adapting the tool to local ground.
The Ard
The earliest plows were ards, also called scratch plows. An ard has a pointed share, made of wood, stone, or later metal, that is dragged through the ground by people or animals, making a furrow without turning the soil over. Ards appear in the ancient Near East, Egypt and Europe, with evidence stretching back several thousand years. Cross-plowing, or running the ard in two directions, helped break up the surface.
The ard works well on light, dry soils, such as those around the Mediterranean, where deep turning could dry out the earth. On heavy, wet clay soils it is far less effective.
The Heavy Plow
In northern Europe, farmers faced heavier, wetter soils that needed better drainage. Over the early medieval period, a heavy plow with three working parts appeared and spread. A coulter, a vertical knife, cut the soil, the share cut it horizontally, and a moldboard, a curved plate, lifted and turned the slice. It threw the soil to one side, forming ridges and furrows that helped water drain. These plows were heavy and needed a team of oxen or horses, and the details of when and where they emerged are debated.
China developed its own advanced moldboard plows, with cast iron parts that are generally dated to the first millennium BCE and Han period. Dutch and later British designs of the 1600s and 1700s drew on a mix of influences, and the Dutch swing plow influenced English plows. The Rotherham plow, patented in England in 1730 by Joseph Foljambe, used a standardized curved moldboard and iron fittings, and is often described as an early commercial improvement.
Better Moldboards
By the late 1700s, people were applying more scientific thinking to plows. Thomas Jefferson worked out a moldboard shape using geometry, and Charles Newbold of New Jersey patented a cast iron plow in 1797. Farmers distrusted it at first, with some believing iron would poison the soil, and others finding broken parts difficult to replace. Jethro Wood of New York patented a cast iron plow in 1819 made of interchangeable sections so a broken part could be replaced, a practical improvement.
Cast iron plows worked fairly well in lighter eastern soils. The rich prairie soils of the Midwest, however, tended to cling to the iron. The thick, sticky sod left the moldboard clogged, so farmers had to stop frequently to scrape it clean.
John Deere and the Steel Plow
John Deere, a blacksmith from Vermont who had moved to Illinois, is credited with a solution. In 1837, in Grand Detour, Illinois, he made a plow using a polished steel blade, reportedly shaped from a broken saw blade. Smooth steel shed the sticky soil better than rough cast iron. There is some dispute about the exact details, and others were working on similar ideas, but Deere’s plows gained a reputation, and he began making them in numbers.
The process of making large sheets of steel was still expensive in those days. Deere imported steel from England at first, and later obtained it from American mills as production improved. He moved his business to Moline, Illinois, in 1848 for access to water power and river and rail transport. His company became one of the major makers of farm equipment.
A different approach came from James Oliver of Indiana, who developed a chilled iron plow in the 1850s. Casting the surface of the iron in a cold mold made it extremely hard and smooth. These plows were cheaper than steel and became popular in many areas.
Opening the Prairie
Breaking the tough sod of the prairie, with its thick mat of grass roots, was heavy work. Special breaking plows with long moldboards and large teams were used, and settlers often had to hire a neighbor with a team. Once the sod was broken, steel plows could turn it cleanly. Combined with railroads that carried grain to market, they helped turn grassland into some of the world’s productive wheat and corn country.
The steel plow did not cause settlement alone. Land laws, railroads, immigration and markets all played roles, and the loss of native grassland ecosystems and the displacement of Indigenous nations were serious costs. But the plow was one of the tools that made this kind of farming workable.
Plows Since
Later versions added a seat so the farmer could ride, known as the sulky plow, and gang plows with several bottoms pulled by multiple animals. When tractors arrived, plows became larger, hitched to engines and later adjusted by hydraulics. Steel itself improved as methods such as the Bessemer process made it cheaper and more consistent.
In the 20th century, the Dust Bowl years in the 1930s raised concerns about deep plowing on dry plains, since bare soil can blow away. Conservation tillage and no-till farming, which reduce or skip plowing, have become common in many regions to protect soil and save fuel. The moldboard plow remains in use, but it is no longer the automatic first step it once was.