section_path: Cultivation
section_name: Cultivation
paragraph_text: Cultivation
  
  All cereal crops are cultivated in a similar way. Most are annual, so after sowing they are harvested just once. An exception is rice, which although usually treated as an annual can survive as a perennial, producing a ratoon crop. Cereals adapted to a temperate climate, such as barley, oats, rye, spelt, triticale, and wheat, are called cool-season cereals. Those preferring a tropical climate, such as millet and sorghum, are called warm-season cereals. Cool-season cereals, especially rye, followed by barley, are hardy; they grow best in fairly cool weather, and stop growing, depending on variety, when the temperature goes above around 30 °C or 85 °F. Warm-season cereals, in contrast, require hot weather and cannot tolerate frost. Cool-season cereals can be grown in highlands in the tropics, where they sometimes deliver several crops in a single year.