Quinoa comes from the Andean region of South America, where it has been an important food for 6000 years. It is very undemanding and altitude-hardy, so it can be cultivated in the Andes up to 4000 meters. Quinoa grows best in well-drained soils and requires a relatively long growing season. It is also susceptible to a leaf miner in eastern North America which may reduce crop success. The leaf miner also effects the common weed Chenopodium album, but C. album is much more resistent.
Similar Chenopodium species were probably grown in the North America, before corn agriculture became popular. Chenopodiums were also used in Europe as greens. Chenopodium album which has a widespread distribution in the United States produces edible seeds and greens much like Quinoa, but in lower quantities. Caution should be exercised in collecting this weed however, because when growing in heavily fertilized agricultural fields it can accumulate dangerously high concentrations of nitrate.
In colonial times, quinoa was scorned by the Spanish colonists as "food for Indians", but in more enlightened times the grain has come to be highly appreciated for its nutritional value. Unlike wheat or rice, quinoa contains a full complement of the amino acids which the human body can't produce itself, making it an unusually complete foodstuff.