Potatoes, like other flowering plants, evolved from earlier plants around 350 million years ago. They’re related to the poisonous plant nightshade, and also to tobacco, chili peppers, bell peppers, and tomatoes. The leaves of all these plants are poisonous, but you can eat the fruit of the peppers and tomatoes, and you can eat the roots of potato plants (Potato fruit looks like small green tomatoes, but it is poisonous).
Potato plants grow wild all over South America and as far north as Colorado and Nebraska in North America. About 15,000 years ago, when people first came to North America from Asia, they began to eat the potato roots and the roots of similar plants like camas and wapato that they found there.
Sometime around 8000 BC, in the Andes Mountains in South America, people began to farm potatoes as well as gathering them. Farmers bred the potatoes to gradually become bigger and taste better. Norte Chico people dug long irrigation canals to get water to potato fields. Potatoes were the main thing people ate in the Inca Empire. But potato farming did not spread north the way corn and bean and squash farming did; people continued to farm potatoes only in the Andes Mountains. Even Maya and Aztec people didn’t farm potatoes.
When Spanish invaders conquered South America in the 1500s AD, they learned about potatoes and brought some back to Europe to show people there. Potatoes didn’t catch on right away in Europe. At first people were very suspicious of this new food, especially because some parts of the potato plant were poisonous. There were also a lot of laws that encouraged people to plant wheat and barley. It took a long time for law-makers to change these laws to allow farmers to plant potatoes too.
European traders also brought potatoes to China, and in China potatoes caught on faster. Only a few rich people ate potatoes in China during the Ming Dynasty, but by the 1700s a lot of people in China began to eat potatoes.
Some bad diseases that attacked wheat and barley convinced European farmers to try planting potatoes in the late 1700s, and by the 1800s a lot of people in northern Europe were eating potatoes regularly, mostly replacing parsnips, turnips and rutabagas, and reducing the amount of wheat and barley that they ate. People also liked potatoes because they grew under the ground and were less likely to be destroyed in a war than wheat and barley.
Gradually European people brought potatoes to other continents as well as Europe. In the 1830s, the rye harvest was very bad in Russia, and farmers started to plant potatoes instead. Soon most people in Eastern Europe and Central Asia were living mainly on potatoes instead of rye bread. In Africa, European rulersencouraged people to plant potatoes in the late 1800s, and again they became popular because they were less likely than millet to be destroyed during wars.
By the 1830s, people in Ireland were living mainly on potatoes, because they didn’t control very much land and potatoes were the only plant that would produce enough food to feed them. But in 1845, a fungus destroyed almost the entire potato crop in Ireland. Rich people refused to give their poor neighbors other kinds of food, which were too expensive for poor people to buy. Millions of people starved to death.
Many of the survivors moved to the United States to start over, and they brought their habit of living on potatoes with them. By the 1850s, many North American farmers were also growing white potatoes, which gradually replaced sweet potatoes for many people. So even though North America was closer to South America than any other continent, people began eating white potatoes first in South America, then in faraway places like China, Europe, and Africa, and only later in North America.